Fossil and Petrology collections, New South Wales The Petrology Collection contains 70,000 rocks and thin sections. It was started in the 1870s as two separate collections, one with 9,000 rocks and the other with 43000 thin sections. Hand written catalogues exist for each. After 1912, only one collection was continued up to the present day. The two old subcollections have much more significance than their sizes would indicate, because much of the material comes from old mine sites, and many of these are no longer available for sampling. Furthermore a few samples, have world significance, such as the thin section from the very sample of Copeton dolerite
Pellets (petrology) majority of peloids as secondary allochems created by biological degradation or “micritization” of other primary carbonate grains, i.e., ooids, bioclasts, or pellets. Pellets (petrology) Pellets are small spherical to ovoid or rod-shaped grains that are common component of many limestones. They are typically 0.03 to 0.3 mm long and composed of carbonate mud (micrite). Their most common size is 0.04 to 0.08 mm. Pellets typically lack any internal structure and are remarkably uniform in size and shape in any single limestone sample. They consist either of aggregated carbonate mud, precipitated calcium carbonate, or a mixture of both. They either are