Geological Society, 145 



From the upper marine deposit of Dr. Morton, which corre- 

 sponds to the lower tertiary of Mr. T. A. Conrad, and to the older 

 Pliocene of Mr. Lyell, numerous specimens were exhibited to us in 

 the course of last session by Mr. Finch *. Of fifty-six species of 

 shells observed by Mr. Conrad in this deposit, which extends through 

 Maryland, Virginia, and the county of Cumberland, in New Jersey, 

 one third still exist on the coast of America, but some species in a 

 more southern latitude than that in which they are found fossil. 



The Miocene beds, if they occur, have hitherto escaped detec- 

 tion. The Eocene, the middle tertiary of Mr. Conrad, which in En- 

 gland is known as the London clay, and in France as coarse lime- 

 stone, assumes in America the character of siliceous sand, and in 

 that form has been traced in a north-eastern and south-western di- 

 rection from Alabama, through South Carolina, Georgia, and Flo- 

 rida, as far as the Gulf of Mexico. Two hundred and nineteen 

 species of shells found in this deposit have been described by 

 Mr. Lea, but among them all, there is perhaps not one entirely analo- 

 gous to any living species. Several of these shells belong to genera 

 unknown upon the coast of America, some to genera found fossil 

 in Europe, some to genera entirely new. It may be doubted whe- 

 ther any of the species correspond with any of the Eocene fossils 

 of Europe, but the number of turreted shells and generic resem- 

 blance satisfactorily establish the epoch to which they belong. 



It appears from the observations of M. Dufrenoy that in the 

 chalk of the Pyrenees fifty species, in a list of about two hundred, 

 have the character of tertiary shells. A corresponding gradation 

 in the fossil contents of the tertiary and cretaceous formations is 

 observable in America. The Chalk, or rather the Chalk-Marl, of the 

 new continent occupies large tracts in New Jersey, Delaware, and 

 Alabama, and contains among other organic remains teeth of the Mo- 

 sasaurus, in no respect differing from those collected at Maestricht. 



Mr. Rogers recovers the Chalk formation on the banks of the 

 Missouri, and about the mouth of the Omawhaw ; its transverse 

 limit is not known. No flints appear in the beds, but flint nodules, 

 like the English, occur plentifully lower down the river, even to the 

 Mississippi. 



The Ferruginous Sand of America reposes in the northern states 

 of the Union as in Sweden and along the Carpathian mountains, 

 upon primary rocks ; in the southern, upon limestone, perhaps our 

 mountain limestone ; it forms an irregular crescent, extending 

 nearly three thousand miles, through Jersey, Delaware, Maryland, 

 Virginia, the two Carolinas, Georgia, Alabama, Mississippi, Te- 

 nessee, Louisiana, Arkansas and Missouri. 



Dr. Morton and Mr. Rogers refer this formation to the Green-Sand 

 of England with more confidence perhaps than their observations 

 warrant. Sands red and green occur in Europe both above the 

 chalk and below it. Zoological evidence rather militates against their 

 conclusion. With one or two exceptions all the species are peculiar 



[* Mr. Finch's collection has since we believe been purchased for the 

 British Museum. — Edit.] 



Third Series. Vol. 7. No. 38. Aug. 1835. U 



