Diamantinasaurus

Diamantinasaurus is a genus of titanosaurian sauropod from Australia that lived during the early Late Cretaceous, about 94 million years ago. The type species of the genus is D. matildae, first described and named in 2009 by Scott Hocknull and colleagues based on fossil finds in the Winton Formation. Meaning "Diamantina lizard", the name is derived from the location of the nearby Diamantina River and the Greek word "sauros", "lizard". The specific epithet is from the Australian song Waltzing Matilda, also the locality of the holotype and paratype. The known skeleton includes most of the forelimb, shoulder girdle, pelvis, hindlimb and ribs of the holotype, and one shoulder bone, a radius and some vertebrae of the paratype.
History of discovery.
The holotype of "Diamantinasaurus" was first uncovered over four seasons of excavations near Winton, Queensland, Australia. The bones, found alongside the holotype of "Australovenator" and crocodylomorphs and molluscs. The two dinosaurs found, known from specimens catalogued as AODF 603 and 604 were described in 2009 by Scott Hocknull and his colleagues. Specimen AODF 603 became the basis for the genus "Diamantinasaurus", and the species "D. matildae". The species name is a reference to the song "Waltzing Matilda", written by Banjo Paterson in Winton, while the generic name is derived from the Diamantina River, running nearby the type locality combined with the Greek "sauros", meaning "lizard". AODF 603, the holotype, includes the right scapula, both humeri, right ulna, both incomplete hands, dorsal ribs and gastralia, partial pelvis, and the right hindlimb missing the foot. The paratype, under the same specimen, includes dorsal and sacral vertebrae, the right sternal plate now thought to represent the remainder of a coracoid, a radius, and one manual phalanx. All these bones come from AODL 85, nicknamed the "Matilda Site" at Elderslie Sheep Station, located about west-northwest from Winton in central Queensland. This locality is in the upper midsection of the Winton Formation, which dates to the Cenomanian of the Late Cretaceous.
The discovery of "Diamantinasaurus" ended a pause in the discovery of new dinosaurs in Australia, as the first sauropod named in over 75 years. Along with "Australovenator", "Diamantinasaurus" has been nicknamed after the Australian song "Waltzing Matilda", with "Australovenator" being called "Banjo" and "Diamantinasaurus" being nicknamed "Matilda". "Wintonotitan", also from the site, was dubbed "Clancy". The find was apparently the largest dinosaur discovery in Australia that was documented since that of "Muttaburrasaurus" in 1981.
An additional specimen, AODF 836, was described in 2016. It includes portions of the skull, including a left squamosal, nearly complete braincase, right surangular, and various fragments. Additionally, the specimen also includes the atlas, axis, five other cervical vertebrae, three dorsal vertebrae, additional dorsal ribs, portions of the hip, and another right scapula. In 2021 the referred material was thoroughly described.
Description.
"Diamantinasaurus" was relatively small for a titanosaurian, possibly reaching in length and in weight. Some of its relatives are known possessed armour osteoderms although is it unknown whether "Diamantinasaurus" had these. Like other sauropods, "Diamantinasaurus" would have been a large quadrupedal herbivore. Since the original description, the only major revisions include the misidentification of the "sternal plate", misplacement of manual phalanges III-1 and IV-1 as III-1 and V-1 respectively, and the identification of the missing portion of the fibula.
The skull of "Diamantinasaurus" is incompletely known, with only the posterior skull roof and braincase being preserved. Similarly to "Saltasaurus" and "Rapetosaurus" and unlike "Nemegtosaurus", the was bordered by the frontal bone. Contrasting from both latter genera, "Diamantinasaurus" has a low above the cranial foramen, which is subsequently less than 1.5 times the height of the (which has a foramen). All of these traits are however shared with "Saltasaurus". Multiple other traits are found throughout derived titanosaurs, including downward angling of the skull, prong shaped lateral braincase processes, an undisturbed pituitary fossa, and a more centrally located opening for the internal carotid artery.
As is typical for Titanosauriformes, all cervical and dorsal vertebrae of "Diamantinasaurus" are and camellate (many small internal chambers). The axis vertebra of the genus is short, a potential characteristic of Saltasauridae. Contrasting "Saltasaurus" and "Rapetosaurus" however, the of "Diamantinasaurus" extend in front of the centrum. Only certain in the known middle dorsals, the (ridge on posterior surface of spine) extends below the spine itself. Like more basal sauropods "Europasaurus" and "Euhelopus", the dorsal vertebrae have a notch on the top of the posterior centrum face, giving it a heart-shaped appearance, contrasting more derived titanosaurs or "Giraffatitan" which possess flattened centra. Although differing in centrum shape, "Opisthocoelicaudia" and "Diamantinasaurus" are the only titanosaurs to share a ventral keel set within a sharply defined depression under the dorsals. Dorsal prezygapophyses are linked to the spine by a , which is absent in "Opisthocoelicaudia" and most dorsals of "Rapetosaurus", and the found in "Diamantinasaurus" is also absent in most derived titanosaurs. There is no indication of a , a diagnostic feature of derived titanosaurs. Shared with "Opisthocoelicaudia", "Alamosaurus" and "Lirainosaurus" to the exclusion of other titanosaurs, "Diamantinasaurus" has a simple undivided ridge between the posterior centrum and diapophysis (). A poorly preserved feature between the prezygapophysis and centrum may be the , found in some brachiosaurids, basal titanosaurs, and "Opisthocoelicaudia". "Diamantinasaurus" possessed at least five, possibly six, sacral vertebrae.
Forelimb.
Almost all the right forelimb is known from "Diamantinasaurus", although the left humerus is known in addition to the right, and the left first metacarpal is known while the right is unpreserved. Diagnostic of "Diamantinasaurus", the glenoid (humerus) articulation of the scapula is rotated to the outside, differing from all other somphospondylans. Similar to "Alamosaurus" and taxa around the base of Titanosauria, at least a single ventral process is known, although it is poorly preserved. The scapula of "Diamantinasaurus" is robust, having a more round cross-section than other somphospondylans. The coracoid, misidentified as a sternal in the original description, is plain and unfeatured, contrasting "Huabeisaurus", "Lirainosaurus" and "Opisthocoelicaudia". The proximal surface of the humerus is prominently curved as in the derived titanosaurs "Opisthocoelicaudia" and "Saltasaurus". The lateral corner is also squared, placing it within Somphospondyli. Like with most somphospondylans but unlike "Euhelopus" and "Rapetosaurus", "Diamantinasaurus" has a middle-shifted . Ridges for muscle attachment are less developed than in "Opisthocoelicaudia" and "Magyarosaurus". Differing from derived titanosaurs, the condyles to articulate with the forearm are not pronounced. "Diamantinasaurus" has an ulna comparing to derived titanosaurs in the level of robustness, as well as having a very pronounced olecranon. Similarly, the radius of "Diamantinasaurus" is more robust than all titanosaurs except "Opisthocoelicaudia". The ulna is long, while the radius is .
Because of the completeness of the forelimb material, the absence of carpal bones among the preserved material was presumed by Poropat "et al." (2014) to be related to their genuine absence in life, as in "Opisthocoelicaudia" and "Alamosaurus". The manus of "Diamantinasaurus" comparatively displays some plesiomorphic features, including: the middle metacarpal being the longest ( Mc III compared to next longest Mc II); the presence of a thumb claw; and the presence of multiple phalanges, having the phalangeal formula 2–1–1–1–1. However, the manus of "Diamantinasaurus" is completely cylindrical and vertical like other titanosaurs. The presence of large numbers of phalanges in "Diamantinasaurus" was used by Poropat "et al." (2014) to suggest that all titanosaurs actually had ossified phalanges contrasting earlier studies. Following this logic, they suggested that for "Opisthocoelicaudia" and "Epachthosaurus", which both preserve a single phalanx from the fourth finger, the absence of others was due to them being lost before fossilization for the preceding digits, instead of absence. The complete absence of preserved phalanges in "Alamosaurus", "Rapetosaurus", "Neuquensaurus" and "Saltasaurus" potentially being due to disarticulation instead of absence of ossification.
Hindlimb.
The left ilium, left and right pubes, left and right ischia, and entire right leg lacking the foot are preserved for "Diamantinasaurus", although some bones are highly fragmented and poorly preserved. The ilium has the outside well preserved, but its size and fragility mean the internal side cannot be seen for anatomical features. The top edge of the ilium is broken, revealing numerous small internal camerae, as present in the titanosaurs "Alamosaurus", "Epachthosaurus", "Lirainosaurus", "Saltasaurus" and "Sonidosaurus". Shared with other derived titanosaurs, the anterior process of the ilium flares to the side and rotates so the vertical ilium body becomes a horizontal shelf. "Diamantinasaurus" also displays the derived sauropod traits of a rounded ilium, reduced articular surface for the ischium, and a protuberance above the ischiatic articulation (only shared with "Opisthocoelicaudia" among Titanosauriformes). The pubis, as in advanced sauropods, is a flattened bone, lacking the anterior hook of diplodocoids, but with potentially autapomorphic grooves surrounding the obturator foramen. Articulation with the ischium takes up 46% of the pubic length, as in most macronarians but contrasting with "Alamosaurus" and "Opisthocoelicaudia", where it is reduced. The entire ischium is only 68% of the length of the pubis as in other titanosaurs, and also expands medially so the entire floor of the pelvis is closed. Unlike some titanosaurs, the ischium of "Diamantinasaurus" displays no constriction of its width, nor a flange projecting internally. "Diamantinasaurus" also lacks a notable muscle scar for the "M. flexor tibialis internus 3" on the side of the distal ischium, which is diagnostic for the taxon amongst Neosauropoda.
The femur, long, is roughly twice as wide as it is long, as in other derived sauropods, although it has been slightly crushed. The crushing did not prevent the preservation of the "linea intermuscularis cranialis" ridge, also present in "Saltasaurus", "Neuquensaurus", "Bonatitan", "Rocasaurus" and "Alamosaurus". As is typical for a sauropod, the head of the femur is slightly above the greater trochanter, and there is a mild trochanteric shelf. A moderate lateral bulge is present, above which the femur is shifted medially, like most macronarians except "Opisthocoelicaudia", "Saltasaurus" and "Rapetosaurus". The condyles for articulation with the tibia and fibula extend high onto the posterior surface of the femur, but unlike "Neuquensaurus" and "Opisthocoelicaudia" do not extend onto the anterior surface. A depression subdivides the fibular condyle, which bears a slight ridge also found in "Magyarosaurus" and other titanosaurs, although the prominence of it is unique to "Diamantinasaurus". The fibular condyle is larger than the tibial, and extends farther down, giving the femur a bevelled appearance, potentially diagnostic of Saltasauridae but also found in "Rapetosaurus" and the non-titanosaur "Dongbeititan".
The tibia is 59% of the length of the femur, and as is normal for neosauropods is wider than it is long on the proximal surface. "Diamantinasaurus" bears multiple fossae and ridges on the tibia that have not been observed in other sauropods, making them a suite of diagnostic traits. As in many titanosaurs, the distal end of the tibia is flared to over double the midshaft width, although a thin flange along the midshaft may be diagnostic to "Diamantinasaurus". Originally reconstructed missing part of the shaft, the fibula is long, and is intermediately robust, although close to gracile. The bone is poorly preserved, but still displays a diagnostic widening of the fibular muscle scar, and a diagnostic medial ridge with surrounding grooves. As in many titanosauriforms, the astragalus of "Diamantinasaurus" is less than 1.5 times as wide as long, and the proximal surface is divided into the ascending process and the fossa for the tibia. There is also a shallow fossa for the fibula on the outside face of the astragalus, giving the bone a subtriangular shape. No depressions or foramina are present at the anterior base of the ascending process, a condition typical of Eusauropoda. A process on the posterior side of the astragalar body is unique among all sauropods, making it an autapomorphy of "Diamantinasaurus".
Classification.
When it was originally described, "Diamantinasaurus" was assigned to Lithostrotia "incertae sedis". In both phylogenies it was placed in, "Diamantinasaurus" was either just outside Saltasauridae or the sister taxon of "Opisthocoelicaudia" within the family. In a 2014 study, it was found that the genus was placed as a lithostrotian in both large phylogenies, in a relatively derived position in Titanosauria. Their first phylogeny was modified from that of Carbadillo and Sander (2014), the matrix being indirectly based on Wilson's 2002 phylogeny. In that cladogram, "Diamantinasaurus" was found to be sister taxon to "Tapuiasaurus", their relationship outside of Saltasauridae. In this phylogeny, the Bremer support for each group was at most 1. Five features of the skeleton supported the placement of "Diamantinasaurus" in Lithostrotia.
In the same study, the relationships using the Mannion "et al." (2013) matrix were tested. These resolved with "Diamantinasaurus" as a saltasaurid, sister to "Opisthocoelicaudia", with "Dongyangosaurus" as the next closest. Two characters were found to support the placement of "Diamantinasaurus" in Lithostrotia, and a third could not be evaluated.
Another phylogenetic analysis in 2016, partially reproduced below, found it as a non-lithostrotian titanosaur and the sister taxon of the contemporary "Savannasaurus".
The 2021 study recovered a similar topology, finding a close relationship with "Savannasaurus" as well as "Sarmientosaurus" from the early Late Cretaceous of Patagonia, which skull had similarities to the referred cranial material of "Diamantinasaurus". The clade containing these taxa was dubbed Diamantinasauria.
Paleobiology.
Growth.
In 2011, the smallest positively identified titanosaur embryo was described. Although it was uncovered in Mongolia, the embryo shares the most features with "Diamantinasaurus" and "Rapetosaurus". The embryo, from a relatively spherical egg, was identified as persisting to a lithostrotian. The embryo was slightly robust, intermediate between the robustness of "Rapetosaurus" and "Diamantinasaurus". The egg is part of an entire nesting site for lithostrotian titanosaurs. Dating of the region also suggests that this egg predates those of Auca Mahuevo in Argentina, and the eggs were laid in the Early Cretaceous.
Paleoecology.
"Diamantinasaurus" was found about northwest of Winton, near Elderslie Station. It was recovered from the fossil-rich section of the Winton Formation, which can be dated to approximately 93 million years ago. "Diamantinasaurus" was found in a clay layer between sandstone layers, interpreted as an oxbow lake deposit. Also found at the site was "Australovenator", which was directly associated with "Diamantinasaurus", bivalves, fish, turtles, crocodilians, and various plants. The Winton Formation had a faunal assemblage including bivalves, gastropods, insects, the lungfish "Metaceratodus", turtles, the crocodilian "Isisfordia", pterosaurs, and several types of dinosaurs, such as the aforementioned "Australovenator", the sauropods "Wintonotitan", "Savannasaurus", and "Austrosaurus", and unnamed ankylosaurians and hypsilophodonts. "Diamantinasaurus" bones can be distinguished from other sauropods because of the overall robusticity as well as multiple specific features. Plants known from the formation include ferns, ginkgoes, gymnosperms, and angiosperms.


Langental Formation

The Langental Formation, also spelled as Langetal Formation, is a Late Eocene (Bartonian to Priabonian) geologic formation cropping out in the Sperrgebiet, ǁKaras Region of southwestern Namibia. The siltstones and sandstones of the formation were deposited in a shallow marine environment. The Langental Formation was deposited under hot and humid conditions. The formation overlies the Silica Beds unit and is overlain by the Blaubok Conglomerate. The Langental Formation provides many fossil invertebrates and fish.
Fossil content.
Among others, the following fossils are reported from the formation:


Santanadactylus

Santanadactylus (meaning "Santana Formation finger") was a genus of pterodactyloid pterosaur from the Albian-age Romualdo Member of the Upper Cretaceous Santana Formation, of Barra do Jardim, Araripe Plateau, Ceará State, Brazil. Four species have been named, but today are no considered congeneric with each other. It was a rather large pterosaur.
History and species.
The genus was named in 1980 by the Dutch paleontologist Paul de Buisonjé. The type species is "S. brasilensis", the specific name referring to Brazil. It is based on holotype UvA M 4894 (Geological Institute of the University of Amsterdam), an upper part of the right humerus and a right scapulacoracoid. UvA M 4895, consisting of two cervical vertebrae from a different individual, was assigned as a paratype, referred because it was found in the same lot of 25 chalk nodules bought from collectors. Additional remains, including a notarium (fused vertebrae supporting the shoulder) were subsequently referred to the taxon by Wellnhofer "et al." (1983) and Wellnhofer (1991).
In 1985, Peter Wellnhofer, a German paleontologist who has written numerous scientific publications on pterosaurs, named three additional species: "S. araripensis", "S. pricei", and "S. spixi". "S. araripensis", named after the Araripe Plateau, was a large species based on BSP 1982 I 89, remains including a partial skull (missing the end of the jaws) and arms; the preserved skull section had no crest. "S. pricei", named after Llewellyn Ivor Price, was the smallest of the three species; it was based on BSP 1980 I 122, a left wing from the elbow down, and additional arm material has been referred to it over the years. "S. spixi", intermediate in size, was based on BSP 1980 I 121, another left wing, the name honoring Johann Baptist von Spix.
Over the years, the species of this taxon have been reassessed. Chris Bennett suggested that the hypodigm of "S. brasilensis" was a chimera of a pteranodontid and something else (in that the holotype and paratype belonged to different forms), "S. araripensis" and "S. pricei" were pteranodontids, and "S. spixi" was a dsungaripterid. Wellnhofer (1991) removed "S. spixi" from the genus as well. Kellner and Campos (1992) agreed that "S. spixi" was not congeneric with "S. brasiliensis", but suggested that it was a tapejarid. Unwin (2003) proposed that "Santanadactylus" "spixi" was a species of "Tupuxuara" based on comparison with specimens of this genus. Averianov (2014) considered "Santanadactylus spixi" a "nomen dubium" probably synonymous with "Tupuxuara longicristatus", and he also indicated that the paratype of "S. brasiliensis" was likely referable to "T. longicristatus". Kellner (1990) renamed "S. araripensis" to "Anhanguera araripensis", followed by Wang "et al." (2008), though Veldmeijer (2003) included it in "Coloborhynchus". Recent study, however, considers "S. araripensis" dubious.
Classification.
De Buisonjé first assigned "Santanadactylus" to Criorhynchidae (=Ornithocheiridae). Wellnhofer (1991) considered it a member of the Ornithocheiridae based on the structure of the humerus, but noted that the elongation of the paratype neck vertebrae distinguished it from other ornithocheirids. Bennett (1989) assigned "S. brasilensis" (holotype only) to Pteranodontidae. Kellner (1990), concluding that he could find but a single autapomorphy for "Santanadactylus brasilensis", the straight ventral margin of the proximal part of the deltopectoral crest, assigned the genus to Pterodactyloidea "incertae sedis", but later (Kellner and Tomida 2000) assigned it to Pteranodontoidea. "S. pricei" according to Kellner belonged to a clade descending from the last common ancestor of "Istiodactylus" and the Anhangueridae. The same was in his analysis true for "Araripesaurus", a genus of which he had previously thought "S. pricei" was a junior synonym.
Paleobiology.
"Santanadactylus" is regarded as a large pterosaur, Wellnhofer for the various species indicating a wingspan of 2.9–5.7 meters (9.5–18.7 ft). De Buisonjé thought "Santanadactylus brasilensis" had a wingspan of . It may have been adapted for gliding over flapping flight.


Cochleosaurus

Cochleosaurus ('spoon lizard') is a name of a tetrapod belonging to Temnospondyli, which lived during the late Carboniferous period (Moscovian, about 310 million years ago). The great abundance of its remains (about 50 specimens) have been found in the Kladno Formation of the Czech Republic, near Nýřany in Central Europe and in the Morien Group of Nova Scotia in North America. It was a creature of medium size, measuring 120-160 centimeters. It is believed that "Cochleosaurus" was a semiaquatic ambush predator, hunting like modern crocodiles. Czech paleontologist Antonin Fritsch named the genus in 1885 in reference to the spoon-shaped processes on the supra-occipital bones at the back of the skull (from Latin "cochlear" "spoon" and Greek "sauros" "lizard").


Langlieria

Langlieria is a genus of prehistoric sarcopterygian (lobe-finned "fish"), from the end of the Devonian period (Famennian). It was discovered in Belgium.


Pristerognathus Assemblage Zone

The "Pristerognathus" Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the upper Abrahamskraal Formation and lowermost Teekloof Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. The thickest outcrops, reaching not more than , occur just east of Sutherland through to Beaufort West in the south and Victoria West in the north. Exposures are also found west of Colesberg and south of Graaff-Reinet. The "Pristerognathus" Assemblage Zone is the third biozone of the Beaufort Group.
The name of the biozone refers to "Pristerognathus polyodon", a medium-sized carnivorous therocephalian therapsid. It is characterized by the presence of this therocephalian species in association with "Diictodon feliceps", a small, fossorial dicynodont whose fossils are especially common in this biozone.
History.
The first fossils to be found in the Beaufort Group rocks that encompass the current eight biozones were discovered by Andrew Geddes Bain in 1856. However, it was not until 1892 that it was observed that the geological strata of the Beaufort Group could be differentiated based on their fossil taxa. The initial undertaking was done by Harry Govier Seeley who subdivided the Beaufort Group into three biozones, which he named (from oldest to youngest):
These proposed biozones Seeley named were subdivided further by Robert Broom between 1906 and 1909. Broom proposed the following biozones (from oldest to youngest):
The "Pristerognathus" Assemblage Zone as it currently stands was defined by Keyser and Smith in the late 1970s. Initially the biozone included the upper 300m of the underlying "Tapinocephalus" Assemblage Zone due to the disappearance of Dinocephalian fossils in those rock deposits and had been named the "Pristerognathus-Diictodon" Assemblage Zone. After further research on the rocks of the middle Permian, it was understood that the disappearance of the dinocephalians was not an indication of the boundary of the "Tapinocephalus" Assemblage Zone, and the extra 300m of rock was subsequently restored to the underlying Tapinocephalus Assemblage Zone.
Lithology.
The "Pristerognathus" Assemblage Zone correlates with the upper Abrahamskraal Formation, the lowermost Teekloof Formation west of 24°E and to the Middleton Formation east of 24°E, Adelaide Subgroup of the Beaufort Group. This biozone is considered to be Middle Permian (Guadalupian) in age.
The rocks of the "Pristerognathus" Assemblage Zone are similar to the underlying "Tapinocephalus" Assemblage Zone although is dominated by multistory sandstone deposits. The sandstones are interspaced with silt-rich greenish-grey mudstones and subordinate reddish-brown mudstone layers. Calcareous nodules, which weather out brown, are often found in the mudstone layers. Pinkish chert bands are found in the lowermost mudstone deposits of this biozone. The "Pristerognathus" Assemblage Zone is also known for containing uranium deposits. The presence of the chert band confirms that there was volcanic activity taking place during the time the rock sediments were deposited. The rocks of the lower "Pristerognathus" Assemblage Zone were deposited at the end of the middle Permian (end-Guadalupian) extinction event, which is currently thought to have been caused by the eruption of the Emeishan Large Igneous Province.
The depositional environment of the "Pristerognathus" Assemblage Zone was likewise similar to the "Tapinocephalus" Assemblage Zone, having been formed by sedimentary material being deposited by vast, fluvial plains. These fluvial plains flowed northwards from a foreland basin that was being formed from the rising of the Gondwanide mountains in the south. The Gondwanides were the result of crustal uplift that had previously begun to take course due to tectonic activity. The pressure of the growing Gondwanides mountain chain caused the formation of the Karoo Basin where the deposits of the "Pristerognathus" Assemblage zone, and all other succeeding assemblage zone deposits, were deposited over tens of millions of years.
Paleontology.
Vertebrate fossils are most commonly found in the mudstone deposits of the "Pristerognathus" Assemblage Zone, especially within the calcareous nodules. This biozone is characterized by the presence of "Pristerognathus polyodon" and its other subspecies "Pristerognathus baini" and "Pristerognathus vanderbyli". "Pristerognathus" fossils are usually found associated with those of "Diictodon". The fossils of both these taxa are the most commonly found; other fossil taxa are markedly more rare. Species diversity dropped off after the end-Guadalupian extinction, which is the reason that this biozone is lacking in species richness. Other taxa that have been found in this biozone include a couple pareiasaur species, namely "Bradysaurus", the putative pantestudine "Eunotosaurus africanus", and the varanopid pelycosaur "Heleosaurus scholtzi". Fossils of the biarmosuchian "Hipposaurus boonstrai" are likewise found including some gorgonopsid species. Other dicynodont species found include "Endothiodon uniseries" and "Pristerodon mackayi". Finally, fossils of temnospondyl amphibians such as of "Rhinesuchus whaitsi", the fishes "Namaichthys" and "Atherstonia", invertebrate trackways, burrows, and feeding trails such as of Planolites and a variety of plant fossils, namely of "Glossopteris", "Phyllotheca", and "Schizoneura", have been recovered. Some fossil taxa that have been found from this biozone, namely "Hipposaurus", have been recovered from geological formations from different countries which correlate in age. Hipposaurus fossils have been found in the Madumabisa Mudstone Formation in Zambia.


Cidaris elegans

Cidaris elegans is a fossil species of pencil sea urchins in the family Cidaridae. It is known from the Oxfordian stage (Jurassic) of France.
Note that "Cidaris elegans" (A. Agassiz, 1879) is a synonym for "Histocidaris elegans".


Cromptodon

Cromptodon is an extinct genus of cynodonts from the Triassic of Cerro Bayo de Portrerillos, Cerro de las Cabras Formation, Argentina, South America. It is known only from PVL 3858, a mandible.
Description.
The skull has been estimated to have a length of .
The morphology and distribution of the cups on the postcanines is considered to be very similar to "Thrinaxodon liorhinus" differing in the fact that the cingulum is lingually wider. The coronoid, prearticular and angular processes, Bonaparte considered, were more developed than those in "Thrinaxodon", being more similar to "Tribolodon" (now "Bolotridon"). The lower postcanines are buccolingually expanded.
Classification.
Bonaparte originally classified "Cromptodon" as a galesaurid. In 1991, J. A. Hopson, pointed out a resemblance between the teeth of "Cromptodon" and juvenile "Aleodon" and reclassified "Cromptodon" as a Chiniquodontid. In 2003, Fernando Abdala and Norberto P. Giannini systematically described Chiniquodontidae and found both "Cromptodon" and "Aleodon" to fall outside of Chiniquodontidae as both lacked features their study found to be diagnostic of the family, although additional material was required to provide a definite taxonomic placement.


Palaeotodus

Palaeotodus is an extinct genus of todies in the family Todidae. The genus has at least three species known from fossils found in west-central Europe and western North America.
Species.
The following species are classified within the genus:


Undopterix

Undopterix is an extinct genus of moths within the family Eolepidopterigidae, containing two species. Undopterix sukatshevae is known from Russia. The fossil remains are dated to the Lower Cretaceous.
The second species, Undopterix cariensis is known from the Crato Formation in Brazil.
Taxonomy.
"Undopterix" was initially classified in the Micropterigidae, but was later transferred to the Eolepidopterigidae family. It was designated as the type-genus for the new family Undopterigidae by Kozlov in 1988, but this is disputed.


Aramus paludigrus

Aramus paludigrus is an extinct species of limpkin, semi-aquatic birds related to cranes (order Gruiformes), which are similar. "Aramus paludigrus" was found in the famous Konzentrat-Lagerstätte of the Honda Group at La Venta, dating from the mid-Miocene period, in central Colombia.
Description.
This bird was described in 1997 based on a nearly complete tibiotarsus bone, very similar to its modern relative, the limpkin "Aramus garaudana", although this element measured about long, which implies a 20% larger size. It also differs from the modern species in which this bone has larger lateral condyles, the axis of the bone is longer and narrower, very similar to that found in modern trumpeters ("Psophia"). The general structure of this animal should not very different from the modern limpkins, being a rather sedentary bird (no remains are known from other parts of South America), and what is known of the strata in which he found, had to wade through swamps in search of snails, insects and bivalves to feed on them, that led to their scientific name, as in Greek "paludigrus" can be translated as "marsh crane."


Ullerntangen Formation

The Ullerntangen Formation is a geologic formation in Norway. It preserves fossils dating back to the Ordovician period.


Kepplerites

Kepplerites is a moderately evolute ammonite from the lower Callovian (upper Middle Jurassic) included in the Stephanoceratoidea.
Inner whorls are finely ribbed and have a flattened or grooved venter, the outer whorl has a rounded venter with smooth ribs that cross from side to side without interruption.
"Kepplerites" is assigned to the Kosmoceratidae and to the subfamily Keppleritinae. "Gulielmina" and "Seymourites" are closely related genera, sometimes regarded as subgenera of "Kepplerites.
"Kepplerites" was named by Neumayr and Uhlig in 1892. The type species "K keppleri" is from Germany. This genus has also been found in Alaska, British Columbia, Madagascar, and Russia.
Biostratigraphic significance.
The International Commission on Stratigraphy (ICS) has assigned the First Appearance Datum of the genus "Kepplerites" as the defining biological marker for the start of the Callovian Stage of the Jurassic, 166.1 ± 1.2 million years ago.
References.


Romeral (volcano)

Romeral is a stratovolcano located in Caldas, Colombia. It is the northernmost Holocene volcano of South America, of the North Volcanic Zone in the Andean Volcanic Belt. The volcano was formed in the Late Pliocene, approximately 3 million years ago.


Pleurosaurus

Pleurosaurus is an extinct genus of diapsid reptiles belonging to the group Sphenodontia, extinct relatives of the modern tuatara. "Pleurosaurus" fossils were discovered in the Solnhofen Limestone of Bavaria, Germany and Canjuers, France. It contains two species, "P. goldfussi" and "P. ginsburgi".
"Pleurosaurus" is one of the few known aquatic sphenodontians. Its body was approximately long, and elongated for hydrodynamic streamlining, with comparatively short limbs and a powerful tail. The body was heavily modified from those of other rhynchocephalians, including an enlongated triangular skull. It swam via the use of poorly effiicient axial undulatory anguilliform locomotion (the movement of the body side to side) in shallow marine environments, and was probably piscivorous. It had only small limbs, which probably did not aid in swimming, and nostrils placed far back on the head, close to the eyes.
History of Discovery.
"Pleurosaurus" was first described from the Solnhofen Limestone by Christian Erich Hermann von Meyer in 1834, based on the species "Pleurosaurus goldfussi." In 1970 fossils were reported from the lithographic limestones in a quarry near the village of Aiguines in the Canjuers plateau, France. In 1974, "Pleurosaurus ginsburgi" was described based on MNHN 1983-4-CNJ 67, a mostly complete skeleton found at the Aiguines quarry.
Description.
"Pleurosaurus goldfussi" and "Pleurosaurus ginsburgi" are distinguished by differing skull proportions, different numbers of presacral vertebrae, and considerably shorter forelimbs on "P. ginsburgi."


Wet Andes

The Wet Andes () is a climatic and glaciological subregion of the Andes. Together with the Dry Andes it is one of the two subregions of the Argentine and Chilean Andes. The Wet Andes runs from a latitude of 35°S to Cape Horn at 56°S. According to Luis Lliboutry the Wet Andes can be classified after the absence of penitentes. In Argentina well developed penitentes are found as south as on Lanín Volcano (40°S). The glaciers of the Wet Andes have a far more stable line of equilibrium than those of the Dry Andes due to summer precipitations, low thermal oscillations and an overall high moisture.


Pongo de Mainique

The Pongo de Mainique is a "water gap" (canyon) of the Urubamba River in Peru. Inside the water gap, the river is constricted to a width of . The Pongo de Mainique is long. The elevation of the river is approximately . The steep cliffs on each side of the river rise sharply to mountains with elevations of more than .
The Pongo de Mainique is the only break in the Vilcabamba mountain range. It also divides the Urubamba River (a headwater of the Amazon River) between the turbulent Upper Urubamba and the more placid Lower Urubamba. It is considered the most dangerous whitewater pass on the Urubamba; however, many boats traverse it, depending on seasonal river conditions. According to legend, the river was once crossed by the so-called Inca Bridge, although the Pongo was outside the boundaries of the Inca Empire. The bridge no longer exists.
The Pongo de Mainique is a global biodiversity hotspot. According to the Wildlife Conservation Society, "the lowland rainforests and mid-montane cloud forests within a radius of five miles (8 km) of the Pongo possibly comprise the single most biologically-diverse site on the face of the Earth."
The rapids of the Pongo de Mainique were used as a filming location for key scenes of Werner Herzog's 1982 film "Fitzcarraldo" starring Klaus Kinski.
In a 2006 survey of "15 of the world's top travel writers" by "The Observer", Monty Python actor and BBC travel documentarist Michael Palin named it his "favourite place in the world".
External links.
 – Pictures of the Pongo de Mainique (4th to 8th)


Azulcocha (Cusco)

Azulcocha (possibly from Quechua "asul" blue (a borrowing from Spanish "azul"), "qucha" lake, "blue lake") is a mountain in the Vilcabamba mountain range in the Andes of Peru. It is located in the Cusco Region, La Convención Province, on the border of the districts of Inkawasi and Vilcabamba. Azulcocha lies northwest of the Panta group. The Ranq'a Wayq'u "(Rancahuayco)" originates northwest of the mountain. Its waters flow to the Apurímac River.


List of faults in Slovenia

This is a list of mayor fault lines and fault zones in Slovenia.


Hydrography of the Oak Ridges Moraine

Preliminary research on the hydrology of the Oak Ridges Moraine began in the 1970s, but a broader research effort including the impact of urban development on the aquifer system and Great Lakes water quality was established in 1993. The research locus is the Geological Survey of Canada and the University of Toronto Groundwater Research Group, though other groups have made substantial contributions to this project.
The moraine serves to recharge streams and rivers in the surrounding region, acting as an underground reservoir. Rain and snow melt slowly soak into the moraine, being filtered and purified in its many sand and gravel aquifers. The cool, fresh water is discharged into the headwaters of streams and rivers which eventually flow into Lake Simcoe, Lake Scugog and Lake Ontario. The aquifers are also the water supply for some communities on the Moraine.
Hydrogeology.
The moraine's hydrological system is inter-twined with a regional flow system not bound by the morphological limits of the moraine. For this reason, environmentalists and researchers promote an aggressive protection strategy extending beyond the moraine, thus ensuring a contiguously protected hydrological system.
A number of features comprise the hydrological system of the Oak Ridges Moraine:
Hydrology.
The Oak Ridges Moraine's hydrological system is a major constituent of the Humber Watershed, so that any impact on this system will be of concern. A specific concern is urbanization, which affects water quality by increasing its load of metals and organic contaminants. A study by Cook et al. (1985) found an increase in mean annual runoff, instantaneous discharge, and hydrograph peak flow as a result of urbanization: "...changes in land use coincided with changes in volumetric and time distribution aspects of hydrologic response."
Numerous watersheds are linked to the Oak Ridges Moraine, and are managed by various organizations.
Conservation.
The "Oak Ridges Moraine Conservation Act" of 2001 stipulates that any development in the moraine or nearby areas must satisfy several conditions, most prominently that each development leave a buffer zone of 30 m between it and any hydrological feature; for a kettle lake, this measure is from the edge of the lake's catchment area.
The Act specifically required that each municipality, single-tier and upper-tier, must have commenced preparations for a watershed plan before April 22, 2003 for all watersheds whose streams originate in that municipality [O. Reg. 140/02, s. 24 (1)], and that the requirements of that plan be implemented in the municipality's official plan. The scope of each plan minimally required:
All development within a municipality was prohibited until the completion of this planning exercise, and no development application submitted after April 23, 2007 may proceed if it fails to meet the requirements of the watershed plan, or fails to address the water budget and conservation plan.


Pico de Teyra

Pico de Teyra is a mountain above sea level, located in the state of Zacatecas (highest of this state) in Mexico.


Achucallani

Achucallani (possibly from Aymara "achuqalla" weasel, "-ni" a suffix to indicate ownership, "the one with a weasel (or weasels)") is a mountain in the Andes of southern Peru, about high. It is situated in the Moquegua Region, Mariscal Nieto Province, Torata District. Achucallani lies southwest of Humajalso, Iruma and Surehuayco.


Parastrapotherium

Parastrapotherium is an extinct genus of South American land mammal that existed from the Late Oligocene (Deseadan SALMA) to the Early Miocene (Colhuehuapian SALMA). The genus includes some of the largest and smallest known astrapotherian, but at present no generally recognized description can adequately characterize it.
Description.
The genus was first described by . He distinguished it from the Santacrucian (late Early Miocene) "Astrapotherium" () based on the greater number of upper and lower molars. Although later researchers disagreed and concluded that Ameghino based his conclusion on very fragmentary materials, they mostly agreed to distinguish the genus from other groups of astrapotherians.
Species.
The following species have been recognised:
Distribution.
Fossils of "Parastrapotherium" have been found in:


Pseudoltinomys

Pseudoltinomys is a prehistoric rodent that lived approximately 30 million years ago, during the Oligocene epoch. It outwardly resembles a gerbil, but may have been related to kangaroo rats or may represent an early offshoot of rodents with no modern relatives.


Bravasaurus

Bravasaurus (meaning Laguna Brava lizard) is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Ciénaga del Río Huaco Formation of La Rioja, Argentina. It contains one species, Bravasaurus arreirosorum.
Etymology.
The generic name "Bravasaurus" is derived from the Laguna Brava National Park in Argentina. The specific name refers to the people, the "arreiros" or drivers in Spanish, who carried cattle through the Andes in the 19th century.
Description.
"Bravasaurus" was roughly long. It is known from the holotype CRILAR-Pv 612, which consists of the right quadrate and quadratojugal, four cervical, five dorsal, and three caudal vertebrae, few dorsal ribs, three haemal arches, the left humerus, a fragmentary ulna, the metacarpal IV, a partial left ilium with sacral ribs, the right pubis, a partial ischium, the left femur, and both fibulae, and the paratype CRILAR-Pv 613, which consists of an isolated tooth, the right ilium, the right femur, and dorsal ribs.
Classification.
The describers' phylogenetic analysis places "Bravasaurus" as a derived member of the Lithostrotia, in the clade Aeolosaurini, which they recover as a subclade of Rinconsauria, different from other cladograms. Their cladogram is shown below.
Paleoenvironment.
The holotype locality, the Quebrada de Santo Domingo site, preserves one of the largest concentrations of titanosaur eggs in the world. The describing authors suggest some connection with either "Bravasaurus" or its contemporary "Punatitan", which was described in the same paper.


Lihir Island

Lihir Island (a.k.a. Niolam Island) is the largest island in the Lihir group of islands, 22 km long and 14.5 km wide, in Papua New Guinea's New Ireland Province. It consists of a complex of several overlapping basaltic stratovolcanoes rising 700 m above sea level. While the volcanoes are not currently active, geothermal activity is still present. The island is in what was the forearc basin associated with the subduction of the Pacific Plate beneath the North Bismarck Plate. Subduction stopped about 10 million years ago with the collision of the Ontong Java plateau with the subduction zone.
The island is located NE of Port Moresby. Annual rainfall averages ; temperature ranges between 19 and 35 degrees Celsius. The population of the Lihir Group increased from 12,570 in 2000 to an estimated 18,000 in 2007. Residents are of Melanesian descent and have predominantly a subsistence lifestyle.
Lihirians follow traditional belief systems, although official census records indicate that 99% of the PNG population are Christians, with Catholicism being the largest denomination. Most villages are located on the coastal fringe, although it is thought that originally some villages were located inland but were moved to the coast at the encouragement of missionaries.
The economic focal point of the island is the Ladolam Gold Mine. Ladolam represents one of the largest epithermal gold deposits in the world and it is hosted by high-potassic igneous rocks. The mine is operated by Newcrest Mining Limited. The mine holds one of the world's largest gold resources (46 million ounces). Grab samples from the submarine Conical Seamount, located about 8 km south of Lihir Island, contain high gold concentrations of up to 230 g/t Au (avg. 26 g/t, n=40) that are hosted by high-potassic trachybasalts.
The mine is located on a geothermically active area and to enable the mine to proceed, steam relief wells have been drilled to release subterranean pressure. The steam has, in part, been captured and is used to operate a 50 MW geothermal power station which generates approximately 25% of the mine's power requirements. Mine tailings are discharged into the sea.
The largest settlement on the Island is Londolovit, where most of the expatriate mine employees live. Basic shopping and health care facilities are located there. The local hospital has inpatient and outpatient facilities and provides health care services to both the expatriate and local communities.
An airstrip large enough to land a small jet is also located north of Londolovit, at Kunaye village
As is the case in many tropical regions, mosquito-borne viruses are present on the island, as is malaria.
Land ownership follows traditional models with land being owned by clans. Insofar as it relates to land ownership, the society is matrilineal with land being passed through the female generations. The land cannot be sold; however, usage rights can be granted.
The Island has two largest Primary Schools and a Secondary School Located on the Mining impacted area. The largest of the two Primary schools is Sekunkun Primary School which is on the North Eastern part of the Island. The school has total of over 600 students and 19 teachers.


Cephalogale

Cephalogale is an extinct genus of hemicyonine bear which lived in the Oligocene and Early Miocene epochs in North America and Europe. It lived from around 28.4—20.0 Mya. Before it was reconsidered to be close to the ancestry of hemicyonines, "Cephalogale" was once considered to be an ancestor of all bears.


Green Seamount

Green Seamount is a small seamount (an underwater volcano) off the western coast of Mexico. It and the nearby Red Seamount were visited in 1982 by an expedition using "DSV Alvin", which observed the seamount's sedimentary composition, sulfur chimneys, and biology. Thus, Green Seamount is well-characterized for such a small feature.
Geology.
Green Seamount has a minimal sedimentary cover ( of unusually fine sands, with the exception of its more thickly covered caldera (where it was over thick). Green Seamount is also home to a small number of hydrothermal vents near its caldera wall, which "Alvin" observed (on Red Seamount) to be oxide-rich with temperatures of , very low temperatures for a hydrothermal vent. Non-hydrothermal sediments on the volcano were observed to be light, "cream-colored" carbonates thinly masked in a finer gray and green sediment.
The expedition also noted sulfur mounds near the caldera and pit crater walls; these are unusual because, unlike most mid-ocean ridge seamounts, Green's "sulfur chimneys" contain a high amount of silicon, iron, copper, and quartz, but are poor in zinc. The complicated process that created the vents occurred between 140,000 and 70,000 years ago, and by looking at the sulfur chimneys scientists can estimate that it has taken about 260,000 years for the Green Seamount to reach its present height. There is also an iron-manganese crust on a small off-axis seamount that adjoins Green Seamount, a configuration common with sulfur-rich seamounts.
Biology.
Green Seamount is not very biologically diverse. The only fauna observed at its hydrothermal sites were single-celled, fan-shaped xenophyophores, and some shrimp. Still, marks of biological life were plentiful wherever sediments were or more deep. The xenophyophores in particular were of a type that was found on many of the seamounts in the eastern Pacific region. "Alvin" took two samples, a sponge of the Hexactinellid family and barnacles of the Sessilia order, back to the surface for analysis.


Quercylurus

Quercylurus major is an extinct nimravid carnivoran, or "false sabre-tooth," from the early Oligocene of France. Its fossils are found from Early Oligocene strata in Quercy. "Q. major". was possibly the largest nimravid ever known, as its fossils suggest it was similar in size to the modern-day brown bear and was scansorial. It was very muscular, walked on plantigrade (flat-footed). So far, there is only one described species within this genus - "Q. major".
The species lived in the moist and humid forests of Oligocene Europe alongside fellow nimravid "Eofelis". It was an apex predator in its environment, and it is likely that it hunted large ungulates by ambush.
Taxonomy.
"Quercylurus" was named by Ginsburg (1979). It was assigned to Felidae by Carroll (1988), but later, it was then later placed within Nimravidae.


Ampezzoa

Ampezzoa triassica is an extinct species of gall mite described from the Carnian of northeastern Italy. It lived as a parasite of Cheirolepidiaceae trees. The only known specimen, preserved in amber, is 0.124 mm long. It resembles very much, in body shape and wax secretions, the contemporary gall mite "Cymeda zealandica". Along with "Triasacarus fedelei" and an unnamed dipteran, it is the oldest arthropod found enclosed in amber.
"Ampezzoa" had a vagrant lifestyle on the surface of its host. It secreted waxy filaments, as a defense against predation and desiccation.


Glenville Hills Kames

The Glenville Hills Kames is a 345 hectare provincially significant "Earth Science" Area of Natural and Scientific Interest in Ontario, Canada.
Located in the northeastern part of the township of King, it contains most of the eastern portion of Jokers Hill, site of the Koffler Scientific Reserve which conducts ecological research in the area. It consists of Late Wisconsinan deposits of Newmarket Till, from the Port Bruce Stadial, and Kettleby Till, from the Port Huron Stadial. These are overlain by kames and kame slopes, which are the dominant topographical features in the area, on the northern slopes of the Oak Ridges Moraine. It is an "excellent representation of kame moraine features", which are uncommon in the region. It is in the East Holland River subwatershed.
The site also demarcates the southernmost advance of the Lake Simcoe sublobe during the Port Bruce Stadial, though most sediments were deposited by the Lake Ontario lobe.


Esmeraldas Formation, Ecuador

The Esmeraldas Formation is an Early Pliocene (Montehermosan to Chapadmalalan in the SALMA classification) geologic formation of the Borbón Basin in northwestern Ecuador.
Description.
The bioturbated, tuffaceous, green mudstones and sometimes sandstones with small or medium-sized rounded pebbles are scattered throughout the formation, or more rarely concentrated into minor beds or seams of conglomerate. Large calcareous concretions, some rounded or with an irregular rootlike shape, generally with hollow centers are common at many places. The beds are highly foraminiferal, with pelagic types, often pure enough to form a foraminiferal ooze-like sediment. On the fresh surface of the rock platform, the formation is hard, and of a gray-black or dark olive-green color. The sediments were deposited in a deep marine environment.
Fossil content.
The formation has provided bivalve, gastropod, echinoid, coral, bryozoa, radiolaria, foraminifera and scaphopod fossils.


Stegskopf

The Stegskopf, at , is the second highest mountain in the Westerwald range in Germany after the Fuchskaute. It is an extinct volcano in the municipality of Emmerzhausen in the county of Altenkirchen in the state of Rhineland-Palatinate.
Geography.
Location.
The Stegskopf is part of the High Westerwald (the highest region in the Westerwald) in the eastern part of the county of Altenkirchen about 2 km south of Emmerzhausen and immediately west-northwest of the village of Stegskopf. To the northwest the land descends via the "Kleines Steinchen" (587.3 m) to Derschen. Just over 1 km east of the Stegskopf runs a section of the border with the state of North Rhine-Westphalia, in within which is the village of Lippe, part of Burbach, to the northeast. To the southeast the terrain descends to Stein-Neukirch.
On the Stegskopf, where there are several abandoned quartzite and basalt quarries, is thick pine forest.
Daaden Training Area.
The Stegskopf was well known for Daaden Training Area (Lager Stegskopf), a military training area first mentioned in 1914 and taken over by the Bundeswehr in 1958, which formed a military area south of Derschen and Emmerzhausen; the mountain being on its northern edge. In the first quarter of 2015, Lager Stegskopf was closed by the Bundeswehr in the wake of their 'new orientation'. The radar units, Prinz Eugen - Tegetthoff (1943–1945), called themselves the "Stegskopfer", because they went to Lager Stegskopf for special training in Radio-frequency engineering. To these units belonged several well known telecommunications engineers and physicists, for example, Alfred Fettweis, Wolf Häfele, Herbert Daniel and Walter Mayer.


Karl Ludwig Fridolin von Sandberger

Karl Ludwig Fridolin von Sandberger (22 November 1826 – 12 April 1898), German palaeontologist and geologist, was born at Dillenburg, Nassau, on 22 November 1826. He was educated at the universities of Bonn, Heidelberg and Giessen, at the last of which he graduated Ph.D. in 1846. He then studied at the University of Marburg, where he wrote his first essay, "Übersicht der geologischen Verhältnisse des Herzogtums Nassau" (1847).
In 1849 he became curator of the Natural History Museum at Wiesbaden, and began to study the Tertiary strata of the Mayence Basin, and also the Devonian fossils of the Rhenish provinces, on which he published elaborate memoirs. In 1855 he was appointed professor of mineralogy and geology at the Polytechnic Institute at Karlsruhe, and he took part in the geological survey of Baden. From 1863 to 1896 he was professor of mineralogy and geology at the University of Würzburg. In 1866, he was elected as a member to the American Philosophical Society. His great work "Die Land- und Süsswasser-Conchylien der Vorwelt" was published in 1870-1875. Later he issued an authoritative 2-volume work on mineral veins, "Untersuchungen über Erzgänge" (1882–1885). He died at Würzburg on 11 April 1898. His brother Guido Sandberger (1821–1869) was an authority on fossil cephalopoda, and together they published "Die Versteinerungen des rheinischen Schichtensystems in Nassau" (1850–1856). Adolf Sandberger, Fridolin's son, was a noted German musicologist and composer.
Fridolin Sandberger is credited with the first valid description of "Laxitextella laxitexta", which is an extinct clam shrimp species named by him "Estheria laxitexta".


Sundvollen Formation

The Sundvollen Formation is a geologic formation cropping out along the northern and eastern shores of Steinsfjorden, Oslo Region, Norway. It preserves fossils dating back to the Gorstian to Ludfordian stages (Rootsiküla in the regional stratigrahy) of the Late Silurian period.
Description.
The formation belongs to the Ringerike Group, overlies the Steinsfjorden Formation and is overlain by the Stubdal Formation. The fish assemblage originates from a horizon with fine-grained, dark greyish-green sandstone from the lowermost part of the formation.
The formation comprises dark-grey siltstones associated with red sandstones and siltstones, with ripple marks, cross-laminations, and crack diapirs, and pseudo-nodules, carbonate concretions. The sequence is fining upwards in cyclothems. Tracks attributed to eurypterids have been found in the red siltstone. Turner (1974) interprets the Sundvollen Formation as representing meandering, braided streams on an alluvial, coastal plain, very close to sea level because of the minor marine incursions found). Boucot and Janis (1983) interpreted the environment to be possibly brackish-estuarine.
Fossil content.
The following fossils have been reported from the formation:
Correlations.
The Sundvollen Formation correlates with the lower part of the Store Arøya Formation.


Acanthinopus

Acanthinopus gibbosus is an extinct species of shrimp placed in its own genus, Acanthinopus, which has not been assigned to a family. It was found in Norian (Upper Triassic) sediments of the Zorzino Limestone in northern Italy.


Monotrematum

Monotrematum sudamericanum is an extinct monotreme species from the Paleocene (Peligran) Salamanca Formation in Patagonia, Argentina. It is the only monotreme found outside Oceania.
Taxonomy.
A species described in 1992 and assigned to a new genus Monotrematum as the type. It is currently the only known species of the genus. The authors compared their fossil material to the genus "Obdurodon", ornithorhynchid species first discovered at Australian fossil sites in 1975.
Description.
"Monotrematum sudamericanum" is known only from two lower and one upper platypus-like teeth. It is the only known non-Australasian ornithorhynchid. The main difference, apart from continent and age, is its size: the teeth of "Monotrematum" are around twice as large as those of other similar species in the related genus "Obdurodon". The teeth of "M. sudamericanum" presently reside in the collections of Museo de La Plata and Museo Paleontológico Egidio Feruglio, both in Argentina.
According to Pascual, "The preserved enamel in the central region shows that the crown pattern is almost identical to that of "Obdurodon": it is composed of two V-shaped lobes, the anterior of which is wider, separated from the posterior one by a valley that connects the lingual and buccal sides of the crown separating the anterior and posterior lobes."


Comura

Comura is a trilobite in the order Phacopida that existed during the lower Devonian in what is now Eifel, Germany. It was described by Richter and Richter in 1926, and the type species is "Comura cometa", originally under the genus "Cryphaeus" by Richter in 1909.


Cormohipparion

Cormohipparion is an extinct genus of horse belonging to the tribe Hipparionini that lived in North America during the late Miocene to Pliocene (Hemphillian to Blancan in the NALMA classification).
Taxonomy.
The genus "Cormohipparion" was coined for the extinct hipparionin horse ""Equus" occidentale", described by Joseph Leidy in 1856. However it was soon argued that the partial material fell within the range of morphological variation seen in "Hipparion", and that the members of "Cormohipparion" belonged instead within "Hipparion". This rested on claims that pre-orbital morphology did not have any taxonomic significance, a claim that detailed study of quarry sections later showed to be false. A reappraisal of many horse genera was thus conducted in 1984, and the proposed synonymy was not acknowledged by later literature.
The genus is considered to represent an ancestor to "Hippotherium". Its fossils have been recovered from as far south as Mexico.


Charassognathus

Charassognathus (meaning 'notched jaw') is an extinct genus of Late Permian cynodonts. Described in 2007 from a locality near Fraserburg, South Africa, "Charassognathus" is one of the earliest and most basal cynodonts. It is known only from the holotype, which dates from the Late Permian Period. The type and only species is "C. gracilis". The holotype (SAM-PK-K 10369), found in the "Tropidostoma" Assemblage Zone of the Teekloof Formation, is made up of a crushed skull, partial lower jaw and one leg.
"Charassognathus" was a quadrupedal predator. It was named for a notch on its coronoid process which most likely was the insertion point for a chewing muscle, the adductor mandibulae externus. "Charassognathus" was a small animal, with a skull only in length. Since the body of "Charassognathus" hasn't been discovered, its full length remains unknown, but estimates have been made at .
Description.
"Charassognathus" has a snout that makes up slightly less than half of the total length of its skull and a long facial process on its septomaxilla. Other than these two features its skull is that of a typical cynodont. The odd shape of its septomaxilla is more typical of therocephalians than other cynodonts indicating that it may be close to a common ancestor between the two groups.


Cerro Agassiz

Cerro Agassiz is a mountain in the mountain range of the Andes, located in the border between Argentina and Chile, in the region of Patagonia.


Paliguana

Paliguana is an extinct genus of lizard-like lepidosauromorph reptile from the Late Permian or Early Triassic Katberg Formation (Beaufort Group) in the upper "Lystrosaurus" Assemblage Zone of South Africa.


Mount Meager massif

The Mount Meager massif is a group of volcanic peaks in the of the Coast Mountains in southwestern British Columbia, Canada. Part of the Cascade Volcanic Arc of western North America, it is located north of Vancouver at the northern end of the Pemberton Valley and reaches a maximum elevation of . The massif is capped by several eroded volcanic edifices, including , volcanic plugs and overlapping piles of lava flows; these form at least six major summits including Mount Meager which is the second highest of the massif.
The Garibaldi Volcanic Belt (GVB) has a long history of eruptions and poses a threat to the surrounding region. Any volcanic hazard ranging from landslides to eruptions could pose a significant risk to humans and wildlife. Although the massif has not erupted for more than 2,000 years, it could produce a major eruption; if this were to happen, relief efforts would be quickly organized. Teams such as the Interagency Volcanic Event Notification Plan (IVENP) are prepared to notify people threatened by volcanic eruptions in Canada.
The Mount Meager massif produced the largest volcanic eruption in Canada in the last 10,000 years. About 2,400 years ago, an explosive eruption formed a volcanic crater on its northeastern flank and sent avalanches of hot ash, rock fragments and volcanic gases down the northern flank of the volcano. Evidence for more recent volcanic activity has been documented at the volcano, such as hot springs and earthquakes. The Mount Meager massif has also been the source of several large landslides in the past, including a massive debris flow in 2010 that swept down Meager Creek and the Lillooet River.
Geography and geology.
Regional geography.
The Mount Meager massif lies in the Coast Mountains, which extend from Vancouver to the Alaskan Panhandle for . It is about wide, cut by fjords, narrow inlets with steep cliffs created by glacial erosion. The Coast Mountains have a profound effect on British Columbia's climate. Lying just east of the Pacific Ocean, they shear off moisture-laden air coming off the ocean, causing heavy rainfall on their western slopes. This precipitation is among the most extreme in North America, feeding lush forests on the mountain range's western slopes.
Valleys surrounding the massif contain old-growth forests. The area also features wetland habitats, plants of the and glaucous willowherbs. Wildlife such as wolves, wolverine, moose, raptors, black-tailed deer, and waterfowl inhabit the area as well as grizzly and black bears.
Regional geomorphology.
Garibaldi Volcanic Belt.
The Mount Meager massif is part of the Garibaldi Volcanic Belt (GVB), the northernmost segment of the . This volcanic belt includes cinder cones, calderas, stratovolcanoes and subglacial volcanoes (volcanoes under glaciers or ice sheets) that have been active in the last 10,000 years. The latest explosive eruption in the Garibaldi Volcanic Belt occurred at a crater on the northeastern slope of the massif about 2,400 years ago, which forms a clearly defined depression.
The GVB extends north from the Watts Point volcano to at least as far as the Meager massif. Because little is known about the volcanoes north of the massif, such as the Silverthrone and , experts disagree about their nature. Some scientists regard the Silverthrone Caldera as the northernmost volcano of the Garibaldi Volcanic Belt, while others contend that the geology of the massif more closely matches that of the GVB. It is also unclear whether the Milbanke Sound Cones are part of the Garibaldi Belt or formed by different tectonic processes. However, there is evidence the Silverthrone and complexes are related to activity at the Cascadia subduction zone. Geologically these two volcanoes contain the same rock types as those found elsewhere in the Cascade Arc, including rhyolites, dacites, andesites and basaltic andesites. Such rock types are produced by subduction zone volcanism indicating volcanism at Silverthrone and is probably related to subduction. If these two volcanoes are true Cascade Arc volcanoes, the massif is not the northernmost volcano of the Garibaldi Belt or the Cascade Arc.
Cascade Volcanic Arc.
Volcanism in the Cascade Volcanic Arc is caused by subduction of the Juan de Fuca Plate under the North American Plate at the . This is a long fault zone lying off the from Northern California to southwestern British Columbia. The plates move at a relative rate of more than per year at an oblique angle to the subduction zone. Because of the huge fault area, the Cascadia subduction zone can produce large earthquakes of magnitude 7.0 or greater. The interface between the Juan de Fuca and North American plates remains locked for periods of roughly 500 years. During these periods, stress builds up on the interface between the plates and causes tectonic uplift of the North American margin. When the plate finally slips, it releases 500 years of stored energy in a massive earthquake.
Unlike most subduction zones worldwide, there is no deep oceanic trench present along the continental margin in Cascadia. The mouth of the Columbia River empties directly into the subduction zone and deposits silt at the bottom of the Pacific Ocean, burying this large depression, or area of sunken land. Massive floods from prehistoric Glacial Lake Missoula during the also deposited large amounts of sediment into the trench. However, as with other subduction zones the outer margin is slowly being compressed like a giant spring. When the stored energy is suddenly released by slippage across the fault at irregular intervals, the Cascadia subduction zone can create enormous earthquakes such as the magnitude 9.0 Cascadia earthquake of January 26, 1700. However earthquakes along the Cascadia subduction zone are uncommon, and there is evidence of a decline in volcanic activity over the last few million years. The probable explanation lies in the rate of convergence between the Juan de Fuca and North American plates, which converge at to per year, about half the rate of convergence from seven million years ago.
Local geography.
Six main summits constitute the Mount Meager massif. The highest and northernmost summit is with an elevation of . Mount Meager itself is in elevation. Capricorn Mountain west of Mount Meager rises with an elevation of . Just west of Capricorn Mountain lies Mount Job, in elevation. Pylon Peak with an elevation of is south of Capricorn Mountain and Mount Meager. Devastator Peak, also known as "The Devastator", has an elevation of and is the lowest and southernmost summit of the massif.
Streams and glaciers have played a significant role in dissecting the massif, and its upper slopes are covered with snow and ice. Numerous feeder dikes to older units, formed when magma intrudes into a crack then crystallizes as a sheet intrusion, are exposed by deep erosion. Perkin's Pillar, a vertical tower of brecciated lava, represented an erosional remnant of the massif until its collapse in June 2005. More than 10 streams drain meltwater from the Mount Meager massif, including , Job Creek, No Good Creek, Angel Creek, Devastation Creek, Canyon Creek and . The massif is located within one of British Columbia's many territorial divisions known as the Lillooet Land District.
Local geomorphology.
The geomorphology of the Mount Meager massif resembles that of Glacier Peak, another Cascade Arc volcano in the U.S. state of Washington. It consists of at least four overlapping stratovolcanoes that are younger from south to north. With a total volume of , the massif is older than most volcanoes in the Cascade Arc, tracing its history back to 2,200,000 years ago. In the Cascade Range, the oldest volcanoes are generally no more than a million years old. This includes Mount Rainier (500,000 years old), Lassen Peak (25,000 years old), Mount Jefferson (290,000 years old) and Mount St. Helens (50,000 years old). However, portions of the massif formed in the last million years. The volcano is made of volcanic rocks ranging from rhyodacite to basalt. Rhyodacite forms a series of eroded volcanic plugs which form the highest peaks. Their slopes are covered with their eruptive products and serve as the surface expressions of intrusions. As a result, they provide a unique opportunity to study the relationships between magma chambers and their lavas. The mafic (rich in magnesium and iron), intermediate (between mafic and felsic) and felsic (rich in feldspar and quartz) volcanic rocks of the massif were erupted from at least eight volcanic vents.
Bridge River Vent.
The Bridge River Vent is a relatively young volcanic crater that formed during an eruption about 2,400 years ago. This eruption ranged in character from explosive to effusive and involved lava dome extrusion, pyroclastic flows, lahars and lava flows. Eastward migration of the spread material across Western Canada to deposit the Bridge River Ash. In the and Lillooet River area the ash occurs as a coarse-textured deposit with blocks of pumice up to in diameter. The texture rapidly becomes finer eastward from the Bridge River. At Big Bar on the Fraser River pellets are up to in diameter while pellets in the Messiter area have a maximum diameter of .
Situated on the northeastern flank of Plinth Peak, the Bridge River Vent has an elevation of . It has oversteepened walls covered with ice and debris from volcanic activity and slope collapses. The crater is roughly bowl-shaped, although it is breached on the northern side. Because the Bridge River Vent is located on the northern slope of the Mount Meager massif, it represents a satellite vent. The eruption that formed the Bridge River Vent was probably fed through a conduit from the magma chamber below the massif. A stress field controlled by regional tectonics has been commonly invoked to explain the dynamics of lateral flow (flowing laterally rather than vertically toward the surface) of magma from a reservoir to produce such eruptions.
Human history.
Naming.
The name Meager Mountain was adopted on May 6, 1924 as labelled on a 1923 British Columbia map. In 1966 the volcano was renamed . According to a BC Geographical Names letter written in March 1983, "the local name, Cathedral, was duplicated elsewhere, so the mountain was renamed Meager after the creek of that name which lies to the south of it". Meager Creek is named after J. B. Meager who owned timber licences on the creek. Despite its official name, Mount Meager is sometimes mistakenly spelled "Mount Meagre" or .
The massif's peak names were submitted by Canadian mountaineer Neal M. Carter, who was a member of the British Columbia Mountaineering Club. Devastator Peak was officially named on in association with Devastation Glacier. Plinth Peak was officially named on as identified in Carter's 1932 sketch map and article "Explorations in the Lillooet River Watershed". Mount Job and Pylon Peak were both officially named on January 17, 1957 from their labels on Carter's 1954 sketch map of the Lillooet River. Capricorn Mountain was originally identified as Mount Capricorn in the 1932 Canadian Alpine Journal, Vol XXI. According to the journal, "the name chosen for the 8440-foot mountain was Mt. Capricorn, a variation of the all-too-common appellation "Goat Mountain", applied by Bert [Perkins] to the stream which drains the Capricorn glacier at its base". Subsequently, the peak was renamed to on June 22, 1967.
Mining and geothermal energy.
A large pumice outcrop more than long and wide has been the subject of mining operations since at least the 1970s. The deposit was first held by J. MacIsaac. In the mid 1970s the second owner W. H. Willes investigated and mined the pumice. It was crushed, removed and stored close to the village of Pemberton. Later the bridge that was used to access the pumice deposit was washed out and mining operations were not renewed. Mining resumed in 1988 when the deposit was staked by L. B. Bustin. In 1990 the pumice outcrop was bought by D. R. Carefoot from the owners B. Chore and M. Beaupre. In a program from 1991 to 1992 workers evaluated the deposit for its properties as a construction material and as an absorber for oil and stonewash. About of pumice was mined in 1998 by the .
The Mount Meager massif has been investigated as a potential geothermal energy resource. At least 16 geothermal sites have been identified in , the Mount Meager area being one of the five areas most capable of commercial development. At Meager Creek, there is potential for commercial development of a 100–200 megawatt power station. Nearby also has "very good" potential for a 200 megawatt plant. Because the two creeks offer the greatest potential for commercial development, the Mount Meager area is the most promising site for geothermal power development in British Columbia.
Volcanic history.
At least 54 eruptions have occurred at the massif in the last 2,600,000 years, ranging in character from effusive to explosive. Four primary eruptive periods have been identified, with individual eruptions separated by thousands of years. Large northwest–southeast trending structures paralleling Harrison Lake and the Pemberton Valley may control volcanic activity at the volcano or at least create zones of crustal weakness that are penetrated by rising magma batches.
First record of activity.
During the first eruptive period between 2,200,000 and 1,900,000 years ago, eruption of intermediate to felsic pyroclastic rocks occurred at the southern end of the massif. Basal breccia, perhaps from an exhumed vent, underlies andesite and tuffs, flows, lava domes and breccia of Devastator Peak. It has a maximum thickness of and overlies a high ridge of bedrock that formed between 251,000,000 and 65,500,000 years ago during the Mesozoic era.
At the southwestern end of the massif, dacite with sparse phenocrysts (large and conspicuous crystals) of quartz, plagioclase and hornblende represents a thick remnant of subhorizontal lava flows. Although the first eruptive period is generally estimated to have started about 2,200,000 years ago, two andesite eruptions may have occurred about 2,400,000 and 2,600,000 years ago. The first might have produced lava flows and breccia, whereas the latter may have erupted mainly breccia.
The Devastator and Pylon assemblage eruptive periods.
The second eruptive period between 1,600,000 and 1,400,000 years ago produced rhyodacite tuff, breccia, lavas and domes of . This thick geological formation lies on the south and west flanks of Pylon Peak and Devastator Peak. Its western portion consists of roughly layered tephra while its eastern end represents the lava flows and subvolcanic intrusions of a partly preserved vent. Here, The Devastator Assemblage is massive and steeply truncates basal breccia from the first eruptive period.
Volcanic activity of the third eruptive period occurred between 1,100,000 and 200,000 years ago. A thick sequence of andesite lava flows were erupted from the volcanic plug of Devastator Peak, creating the Pylon Assemblage. With a maximum thickness of more than , the Pylon Assemblage is the largest rock unit comprising the Mount Meager massif. The lava flows are layered, separated by a thin layer of lapilli tuff and reddened breccia. A concentration of subvolcanic intrusions and coarse volcanic breccia clasts more than in length suggest that Devastator Peak is a major vent.
Formation of the Plinth, Job, Capricorn and Mosaic assemblages.
The fourth and final eruptive period 150,000 to less than 3,000 years ago produced rhyodacite lava flows, domes, breccias and subvolcanic intrusions of the Plinth, Job and Capricorn assemblages. Around Mount Job, porphyritic hornblende, biotite and quartz rhyodacite lava flows of the Job Assemblage were erupted. They are prominently layered and locally columnar jointed. On the east side of Affliction Glacier, they overlie porphyritic andesite lava flows of the Pylon Assemblage. Later, rhyodacite lava flows of the Capricorn Assemblage were erupted and flowed over biotite rhyodacite of the Job Assemblage. The upper of Capricorn Mountain and Mount Job are formed by these lava flows.
Another sequence of rhyodacite lava flows were subsequently erupted and form the Plinth Assemblage. Mount Meager, a massive lava dome or volcanic plug, consists of steeply inclined flow layering and was the southern source of Plinth Assemblage lava flows and breccias. Plinth Peak was also formed during the Plinth Assemblage eruptive stage and is mostly composed of prominent columnar or partly jointed lava flows. Its north ridge and flat-topped summit contain three areas of steep flow layering and subhorizontally-oriented columnar jointing. These areas are possibly the remains of volcanic plugs or lava domes that were the northern source of Plinth Assemblage lava flows. The Mosaic Assemblage, a sparsely porphyritic plagioclase-augite-olivine basalt and trachybasalt formation, also formed during the fourth eruptive period. It is the remains of scoriaceous lava flows, breccias, volcanic bombs and .
The best known and most documented eruption of the Mount Meager massif is a large explosive eruption that occurred about 2,400 years ago. This eruption, which likely reached 5 on the , was similar to the 1980 eruption of Mount St. Helens. It sent a massive Plinian column at least high into the atmosphere. Prevailing westerly winds carried volcanic ash from this explosion eastwards to as far as Alberta. Nearby areas were devastated by heavy pyroclastic fall when parts of the Plinian column collapsed. Later, a series of pyroclastic flows were erupted and travelled downstream. After this, a lava flow was erupted that repeatedly collapsed on the steep slopes of Plinth Peak, creating a thick, welded breccia deposit that blocked the Lillooet River. This created a lake just upstream which later collapsed to produce a massive . Large boulders were carried downstream for more than , but the destructive floodwaters continued further. Later, a small dacite lava flow was erupted, which cooled into well-preserved columnar joints. The entire eruption cycle originated from the Bridge River Vent on the northeastern flank of Plinth Peak. This is the latest known eruption of the Mount Meager massif, as well as the largest known Holocene explosive eruption in Canada. However, it is unknown when this eruption ended.
In 1977, J. A. Westgate of the University of Toronto suggested that a smaller eruption may have occurred at the Bridge River Vent after the eruption 2,400 years ago, sending tephra southeast. A tephra deposit overlying the Bridge River Ash at Otter Creek shows strong genetic relationships with the Bridge River Ash, differing only by its absence of biotite. In earlier publications, this tephra is classified as part of the Bridge River Ash. However, it has been dated to be about 2,000 radiocarbon years old, indicating that this tephra is a few hundred years younger than the Bridge River Ash. Apparent absence of biotite and occurrence well south of the Bridge River Ash likewise favour a separate identity. Large-volume, fine-grained debris flows north of the volcano might have been caused by volcanic activity. If this is correct, the knowledge of eruptions at the Mount Meager massif in the last 10,000 years is insufficient.
Recent activity.
Two small hot spring clusters are found at the Mount Meager massif, indicating magmatic heat is still present. These two clusters of hot springs, known as the Meager Creek Hot Springs and , are most likely related to recent volcanic activity at the massif. The , the largest in British Columbia, remain free of snow for most of the year. The springs at the Mount Meager massif might be evidence of a shallow magma chamber beneath the surface.
Between 1970 and 2005 more than 20 small earthquakes were recorded at the volcano. The magnitudes of these events were generally no higher than 2.0 on the Richter magnitude scale and they originated to less than below the surface. Other volcanoes in the with recorded seismicity include Mount Garibaldi, Mount Cayley massif and . Seismic data suggest that these volcanoes still contain active magma chambers, indicating that some Garibaldi Belt volcanoes are probably active with significant potential hazards. The seismic activity corresponds with some of Canada's recently formed volcanoes and with persistent volcanoes that have had major explosive activity throughout their history such as Mount Garibaldi and the Mount Cayley and Mount Meager massifs.
Fumarolic activity and sulfur smells were detected at the massif in 2016, with a fumarole field discovered on the Job Glacier. This was followed by monitoring of the mountain by Natural Resources Canada volcanologists, the results of which did not detect much seismicity. The fumarole field was considered unsafe to approach or enter due to the presence of hydrogen sulfide and potentially unstable ice crevasses.
Threats and preparedness.
Eruptions.
The Mount Meager massif remains a major volcanic hazard, capable of producing highly explosive eruptions. A full-scale eruption would threaten many populated areas throughout southern British Columbia and Alberta. Pemberton, a community downstream from the massif, faces high risk. If the volcano were to erupt violently, it would disrupt Lillooet River fishery as well as nearby mining and logging activity. In addition, the Mount Meager massif lies in the immediate proximity of a major air traffic route. Volcanic ash reduces visibility and can cause jet engine failure, as well as damage to flight control systems. Even a minor eruption from the volcano could cause massive devastation by rapidly melting glacial ice to produce large debris flows. An example of such an event is the 1985 Armero tragedy in Colombia, which resulted from a small eruption under the summit ice cap of Nevado del Ruiz.
Jack Souther, a leading authority on geothermal resources and volcanism in the Canadian Cordillera, expressed concern about the potential for another eruption:
At present the volcanoes of the Garibaldi Belt are quiet, presumed dead but still not completely cold. But the flare-up of Meager Mountain 2,500 years ago raises the question, "Could it happen again?" Was the explosive eruption of Meager Mountain the last gasp of the Garibaldi Volcanic Belt or only the most recent event in its on-going life? The short answer is nobody really knows for sure. So just in case I sometimes do a quick check of the old hot-spots when I get off the Peak Chair.
Because of concerns about potential eruptions and danger to communities in the area, the plans to create hazard maps and emergency plans for the Mount Meager massif as well as the Mount Cayley massif to the south. Although very few eruptions in Canada have been witnessed by people, it remains nonetheless an area of intense volcanic activity. According to the Geologic Hazards '91 Workshop, "priority should be given to eruption impact studies of the two recently active volcanic centres closest to urban areas, Mount Baker and Mount Meager. The former case will require a combined US-Canada-Washington State-B.C. effort".
The Mount Meager massif is not monitored closely enough by the to ascertain how active its magma system is. The Canadian National Seismograph Network has been established to monitor earthquakes throughout Canada, but it is too far away to provide an accurate indication of activity under the mountain. It may sense an increase in seismic activity if the massif becomes highly restless, but this may only provide a warning for a large eruption; the system might detect activity only once the volcano has started erupting. If the Mount Meager massif were to erupt, mechanisms exist to orchestrate relief efforts. The Interagency Volcanic Event Notification Plan (IVENP) was created to outline the notification procedure of some of the main agencies that would respond to an erupting volcano in Canada, an eruption close to the Canada–United States border or any eruption that would affect Canada.
Although the Mount Meager massif is a potentially active volcano, as of 2016 there was no evidence of an imminent eruption. Many shallow earthquakes normally occur before a volcano erupts. As magma rises to the surface over time, it will probably create much more vigour and heat at the regional hot springs, as well as the formation of new springs or fumaroles. These signs generally occur for weeks, months or years before a potential eruption, although the possibility of an eruption occurring in the near future remains low. A significant structural collapse associated with loss of glacial buttressing might affect the magma plumbing system and lead to an eruption.
Landslides.
Scientists have argued that the Mount Meager massif, made of altered volcanic rock which breaks apart easily, is the most unstable mountain massif in Canada and may also be its most active landslide area. More than 25 landslides have occurred there in the last 8,000 years, and debris flows, mainly from the massif, have also filled Meager Creek valley to a depth of .
Large volcano-associated debris flows known as lahars pose a threat to populated areas downstream from glaciated volcanoes. Although lahars are typically associated with the effects of volcanic eruptions, they can occur whenever conditions allow collapse and movement of mud originating from existing volcanic ash deposits. Melting snow and ice, intense rainfall or the breakout of a summit crater lake can all generate lahars. Landslides at the Mount Meager massif may also be indirectly related to climate change. Several tension cracks extend up to the summit, and as global warming causes glaciers to melt, the meltwater reaches deep into the massif. It then flows along the ruptured surfaces creating landslide zones.
Because the Mount Meager massif is capable of producing large landslides, Meager Creek valley is probably the most dangerous valley in the . Rapidly growing communities down the Lillooet River valley, such as Pemberton, are vulnerable despite their distance from the massif. As Pemberton continues to grow it will eventually extend into the surrounding mountains, creating a major hazard for people living there.
The landslide risk is somewhat mitigated by the Lillooet River Early Warning System which was established in 2014 to alert the Pemberton Valley of landslides. Monitoring is done by measuring the Lillooet River water level using two sensors: one on the Hurley River Forestry Bridge and the other in the river. Damming of the Lillooet River by a landslide would be indicated by the lowering of the water level while the release of a landslide dam would be followed by water level rise.
Historic.
1975 landslide.
A massive rock avalanche occurred at the massif on July 22, 1975. With a volume of , it buried and killed a group of four geologists at the confluence of Devastation Creek and Meager Creek. The landslide originated on the western flank of Pylon Peak and flowed down Devastation Creek for . Geologic studies have shown that the landslide was the result of a complex history of glacial erosion, loading and unloading of the toe (a protrusion at the front of the slide mass) caused by the Little Ice Age advance and subsequent retreat of Devastation Glacier due to global warming.
2010 landslide.
On August 6, 2010 a massive debris flow cascaded down from Capricorn Glacier at a speed of per second. Experts initially estimated that the volume of debris totaled , which would make it the second largest landslide on record in Canadian history, behind the that removed of rock from Johnson Peak, a mountain in the Nicolum Valley near Hope, British Columbia. However, the landslide was later estimated to be more than , which would make it the largest of all time in Canada.
The 2010 landslide was wide and long, creating a dam across Meager Creek and the Lillooet River. This created a lake just upstream. Early concerns that the dam might collapse and flood the Lillooet River valley ended a day later, when part of the dam ruptured and slowly released the accumulated water. An evacuation alert was rescinded, and nearly 1,500 residents were allowed to return to their homes on the weekend after the landslide occurred. No injuries were reported.


Zwethau Formation

The Zwethau Formation is a geologic formation in Germany. It preserves fossils dating back to the Cambrian period.
Fossil content.
The following fossils have been reported from the formation:


Gerard Frederick van Tets

Jonkheer Gerard Frederick van Tets (19 January 1929 – 14 January 1995), otherwise known as Jerry van Tets, was a twentieth century British, Canadian and Australian ornithologist and palaeontologist. Born to Dutch parents, and Thérèse van Heukelom, in London on 19 January 1929, Van Tets spent his childhood in the Netherlands. Following World War II, he moved to England to complete his schooling at Hazelmere. He completed two years of national service with the Royal Engineers in England and Austria before emigrating to Canada where he studied at the University of Toronto (1952–54) and the University of British Columbia (1954-1963), obtaining his PhD in 1963. He became a member of the American Ornithologists' Union in 1958. In November 1963, he married Patricia Anne Johnston in Vancouver, British Columbia, moving shortly thereafter to Australia, where he joined the Commonwealth Scientific and Industrial Research Organisation in the Division of Wildlife and Ecology, now the Division of Sustainable Ecosystems.
Van Tets swam for the swimming teams of British Troops Austria, the University of Toronto and the University of British Columbia.
Van Tets received recognition for his studies on bird strike damage to aircraft, and later for his studies of the bird bones in the Australian National Wildlife Collection, including those of the extinct Tasman booby which he described scientifically in 1988, and became a specialist authority on the mutton bird and the cormorant family. Together with Michael Crowley, Chris Davey, Peter Fullagar, Ederic Slater, Petrus Heyligers and others, Van Tets helped to establish and maintain a long term ecological study on Montague Island, NSW. Van Tets served as compiler for the first four bird (Aves) volumes of the Zoological Catalogue of Australia and as a sub-editor for behaviour for the first three volumes of the Handbook of Australian, New Zealand and Antarctic Birds.
On retirement in 1988, Van Tets continued to work as a research fellow and as curator of osteology for the Australian National Wildlife Collection and the Faunal Reference Collection of the Prehistory Department of the Australian National University. He died in Canberra, Australia on 14 January 1995. Van Tets was survived by his wife and three children, Janet Bradly, Ian van Tets and Kit Cassidy.
The extinct New Zealand stiff-tailed duck, "Oxyura vantetsi", was named in his honour.
The Gerard Frederick van Tets Field Research Station on Montague Island, NSW was named in recognition of Jerry's work there.