HISTORICAL GEOLOGY 79 



same strata are highly inclined. "The analogy, or iden- 

 tity of rocks, I determine by their fossils in the first 

 instance, and their position and mineralogical characters 

 in the second or last instance. " 



It appears that Isaac Lea (1792-1886) in his Contri- 

 butions to Geology, 1833, was the first to transplant to 

 America Lyell's terms, Pliocene, Miocene, and Eocene, 

 proposed the previous year. The celebrated Claiborne 

 locality was made known to Lea in 1829, and in the work 

 here cited he describes from it 250 species, of which 200 

 are new. The horizon is correlated with the London 

 Clay and with the Calcaire Grossier of France, both of 

 Eocene time (25, 413, 1834). 



Timothy A. Conrad began to write about the Ameri- 

 can Tertiary in 1830, and his more important publica- 

 tions were issued at Philadelphia. His papers in the 

 Journal begin with 1833 and the last one on the Tertiary 

 is in 1846. 



The Tertiary faunas and stratigraphy have been 

 modernized by William H. Dall in his monumental work 

 of 1650 pages and 60 plates entitled "Contributions to 

 the Tertiary Fauna of Florida ' ' ( 1885-1903 ) . Here more 

 than 3160 forms of the Atlantic and Gulf deposits are 

 described, but in order to understand their relations to 

 the fossil faunas elsewhere and to the living world, the 

 author studied over 10,000 species. Since then, many 

 other workers have interested themselves in the Tertiary 

 problems. Much good work is also being done in 

 the Pacific States where the sequence is being rapidly 

 developed. 



The Discerning of the Eastern Cretaceous. The Cre- 

 taceous sequence was first determined by that "active 

 and acute geologist," Samuel G. Morton (1799-1851), but 

 that these rocks might be present along the Atlantic 

 border had been surmised as early as 1824 by Edward 

 Hitchcock (7, 216). Vanuxem, as above pointed out, 

 indicated the presence of the Cretaceous in 1829. In 

 this same year Morton proved its presence before the 

 Philadelphia Academy of Natural Sciences. 



Between 1830 and 1835 Morton published a series of 

 papers in the Journal under the title "Synopsis of the 

 Organic Remains of the Ferruginous Sand Formation of 



