206 UPPER EOCENE OF NEBRASKA, U. S. [Ch. XV. 



basin are represented, according to M. Raulin, by the Falun de Leognan, 

 and the underlying limestone of St. Macaire. By many, however, the 

 upper of these, or the Leognan beds, are considered to be no older than 

 the faluns of Touraine. The freshwater strata of Aix-en- Provence are 

 probably Upper Eocene ; also the tertiary rocks of Malta, Crete, Cerigo, 

 and those of many parts of Greece aud other countries bordering the 

 Mediterranean. 



Nebraska, United States. — In the territory of Nebraska, on the Upper 

 Missouri, near the Platte River, lat. 42° N., a tertiaiy formation occurs, 

 consisting of white limestone, marls, and siliceous clay, described by Dr. 

 D. Dale Owen,* in which many bones of extinct quadrupeds, and of 

 chelonians of land or freshwater forms, are met with. Among these, 

 Dr. Leidy recognizes a gigantic Palxotherium, larger than any of the 

 Parisian species ; several species of the genus Orcodon, Leidy, uniting the 

 characters of pachyderms and ruminants ; Eucrotaphus, another new 

 genus of the same mixed character ; two species of rhinoceros of the 

 sub-genus Acerotherium, an Upper Eocene form of Europe before men- 

 tioned ; two of Archazoiherium, a pachyderm allied to Chmropotamus 

 and Ifyracotherium ; also Pcebr other ium, an extinct ruminant allied to 

 Dorcatherium, Kaup ; also Agriochoegus of Leidy, a ruminant allied 

 to Merycopotamus of Falconer and Cautley ; and, lastly, a large car- 

 nivorous animal of the genus Machairodus, the most ancient example 

 of which in Europe occurs in the Upper Eocene beds of Auvergne. 

 The turtles are referred to the genus Testudo, but have some affinity 

 to JEmys. On the whole, this formation has, I believe, been correctly 

 referred by American writers to the Eocene period, in conformity with 

 the classification adopted by me, but would, I conceive, be called Lower 

 Miocene by those who apply that term to all strata newer than the 

 Paris gypsum. 



* David Dale Owen, Geol Survey of Wisconsin, (fee. ; Philad. 1852. 



