Tuffeau_de_St_Omer
The "Tuffeau" de Saint-Omer is a geologic formation in northern France. The sandstones of the formation, named after Saint-Omer, preserve bird and primate fossils dating back to the middle Thanetian age of the Paleocene epoch of the Paleogene period, dating to about 58 Ma.
The European land mammal age, a continental biostratigraphic zonation for the Cenozoic, as ammonites for the Mesozoic and conodonts for the Paleozoic, classification starts after this age, the Thanetian is correlative with the MP2 to 5 of the Mammal Paleogene zone of Europe. At this time in geologic history the climate was at an all-time high with estimated tropical temperatures of 34 °C (93 °F) and 2000 ppm atmospheric CO2.[1]
The formation is locally referred to and geologically known as tuff, although the lithology of the formation is glauconitic sandstone, deposited in a shallow marine environment at the southernmost edge of the North Sea Graben.