Cretaceous Mammals from Montana.

A series of Cretaceous mammal faunas, beginning with standard late Cretaceous faunas and continuing with three of Paleocene aspect, are summarized. Four families (Eucosmodontidae, Taeniolabididae, Leptictidae, Arctocyonidae) and one order (Condylarthra) of Tertiary mammals are extended into the Cretaceous. New genera Cimexomys, Stygimys, Procerberus, and Protungulatum are described, as is a small species of Catopsalis. The skeleton of a multituberculate is restored and multituberculate classification is revised.