36 THE EOCEXE DEPOSITS OF MAEYLAND 



other portions of the Coastal Plain and with Europe are attempted. 

 The author states in short that — 



Many more instauces might be advanced to establisli the identity of what has been 

 called the alluvial district in America with the Tertiary formation of England and the 

 continent of Europe. The fossil shells from the various beds would not, perhaps, be 

 exactly like those of Europe, but a sufficient number would be found so to establish 

 their relation and order of succession. 



During the year 1825 Jer. Van Eensselaer delivered in the IsTew York 

 Athenaeum a course of geological lectures that were subsequently pub- 

 lished in hook form. The author adopted the classification proposed 

 by Finch^ confining his descriptions, however, more particularly to the 

 formations of the northern Coastal Plain. 



The American Journal of Science for 1826 contains a communication 

 by James Pierce " On the shell-marl region of the eastern parts of Vir- 

 ginia and Maryland," in which reference is made to the sections on the 

 James and Potomac rivers and to the " shell rock " at Upper Marlboro. 



A few years later (1828) Professor Lardner Vanuxem, through his 

 friend. Dr. S. G. Morton, presented the criteria for a more complete and 

 definite recognition of the several members of the coastal series, and 

 described both the Cretaceous and Tertiary formations. In this article 

 an attempt is niade to define more accurately the limits of the Tertiary. 

 The author states that much that had been designated by that name 

 properly belongs to other formations. 



Up to the year 1830 all investigations of the stratigraphy of the Ter- 

 tiary had been carried on in the main independently of a study of the 

 fossils. Generic identity had been cited as ground for correlation, and 

 although this aided largely in determining the limits of the Tertiary 

 itself, further subdivisions were impracticable. 



The publication of Conrad's article " On the geology and organic re- 

 mains of a part of the peninsula of Maryland," Avith an appendix con- 

 taining descriptions of new species of fossil shells, inaugurated a new 

 era in the investigation of the Coastal Plain strata. It is true that Say 

 had already described several Tertiary species, including the common 

 Ostrea compressirosira of the Eocene of the Middle Atlantic Slope, but, 

 as stated in Conrad's paper, he did not " draw any geological inferences 



