Cretaceous–Paleogene boundary Cretaceous–Paleogene boundary The Cretaceous–Paleogene (K–Pg) boundary, formerly known as the Cretaceous–Tertiary (K-T) boundary, is a geological signature, usually a thin band of rock. "K", the first letter of the German word "Kreide" (chalk), is the traditional abbreviation for the Cretaceous Period and "Pg" is the abbreviation for the Paleogene Period. The K–Pg boundary marks the end of the Cretaceous Period, the last period of the Mesozoic Era, and marks the beginning of the Paleogene Period, the first period of the Cenozoic Era. Its age is usually estimated at around 66 Ma (million years ago), with radiometric dating yielding a more
St Brides Major (community) St Brides Major, the Dunraven estate and Clemenstone Meadow SSSI. Much of the coastline of the community is designated as the Southerndown Coast SSSI, both for its geology and botanic value. The stretch of shore, cliff, cliff-top, and several short, steep valleys, reveal the local geological strata. Carboniferous Limestone from upwards of 300 million years ago lies at the present sea level. By the Triassic period, 200 million years ago, these rocks were already tilted and eroded. A new deposition phase created more sedimentary rocks, including a red Triassic conglomerate, and a creamy white Jurassic limestone known as Sutton Stone,