tortonian

from The Century Dictionary.

• noun In geology, noting the upper member in Mayer-Eimar's classification of the Miocene Tertiary of France and Mediterranean Europe, which lies between the Helvetian below and the Messinian-Pontian Pliocene above. It is typically developed about Tortona, in northern Italy, and consists of marls and sands containing marine and fresh-water shells and of local deposits in fissures of Jurassic limestone; the latter are of terrestrial origin and contain abundant fossil mammals.