1547 



inaugurated in Europe by a great movement of transgression, bringing in, with' 

 the flexures of the Alps, conditions resulting in organic transformations lead- 

 ing to the existing fauna and flora. In its turn this system is divided into the 

 Miocene and Pliocene series. 



The Eocene series in Europe terminated by the great earth movements 

 which uplifted the Pyrenees and Appenines and which were accompanied by a 

 recession of the sea at many points on the shores of northern and western 

 Europe. 



On the Gulf and southeast Atlantic coast of North America no marked 

 stratigraphic break has been established between the Eocene and Oligocene 

 series. As the studies of the Eocene in this country have chiefly been made in 

 this region, it is not surprising that most American geologists have been prone 

 to minimize the distinctions between the Eocene and Oligocene series. Never- 

 theless, if the invertebrate fauna is taken into account and all allowances made 

 for the existence of a few indications of transition, the change in the fauna is 

 so marked that physical changes elsewhere must be assumed to account for it, 

 since no other hypothesis has even been proposed. The parallelism between 

 the Eocene faunas of Europe and North America is so close that no ground 

 appears for taking exception to their correlation, which is generally accepted. 

 This was clearly indicated in my " Table of North American Tertiary Hori- 

 zons," where I state of the Eocene : " In a wide sense it includes both Eocene 

 and Oligocene of the present table, the two not being separated by essential 

 stratigraphic breaks in the Gulf column or by changes in the climatic relations 

 of the fauna." * 



In Europe the Oligocene series followed the uplifts above referred to, and 

 the changes which resulted in the elevation of the Alps brought it to a close. 

 Its beginnings were marked by the encroachments of the sea upon the land, 

 forming gulfs or lagoons deeply intersecting the continental region, and even, 

 towards the middle of the epoch, reducing the dry land of middle and western 

 Europe to an irregular group of large islands, while Italy, Southern Russia, 

 and North Germany were completely submerged. 



Paleontologically the consequence of these changes which were accom- 



* Eighteenth Ann. Rep. U. S. Geol. Survey, 1896-7, part ii., p. 332, 1898. This, as 

 well as the fact that "Eocene" in the United States Geological Survey nomenclature is 

 the equivalent of " Eogene" of European geologists, seems to have been overlooked 

 by Miss Maury in her thesis on the Oligocene (p. 89) when she states that I use the 

 term Oligocene as coordinate with " Eocene" and " Miocene." 



