40 The Upper Cretaceous Deposits of Maryland 



Mitchell, Samuel L. Cuvier's Essay on the Theory of the Earth. 

 To which are now added Observations on the Geology of North America. 

 8vo. 431pp. Plates. New York, 1818. 



1820 

 Haydex, H. H. Geological Essays; or an Inquiry into some of the 

 Geological Phenomena to be found in various parts of America and else- 

 wbere. 8vo. 412 pp. Baltimore, 1820. 



1821 



Troost, G. Description of a variety of Amber and of a Fossil Sub- 

 stance supposed to be the nest of an Insect discovered at Cape Sable, 

 Magothy Eiver, Anne Arundel County, Maryland. 



Amer. Jour. Sci., vol. iii, 1821, pp. 8-15. 



1824 

 Finch, John. Geological Essay on the Tertiary Formations in 

 America. (Read Acad. Nat. Sci., Phila., July 15, 1823.) 

 Amer. Jour. Sci., vol. vii, 1824, pp. 31-43. 



1825 



Troost, G. Description and Chemical Analyses of the Retinasphalt 

 discovered at Cape Sable, Magothy River, Anne Arundel County, Md. 

 (Read Dec. 19, 1823.) 



Trans. Amer. Phil. Soc, n. s., vol. ii, 1825, pp. 110-115. 



1827 

 Morton, S. G. Description of a new species of Ostrea ; with some 

 Remarks on the 0. convexa of Say. Read May 1, 1827. 

 Jour. Acad. Nat. Sci. Phila., vol. vi, 1827, pp. 50-51. 



1828 



Morton, S. G. Description of two new species of Fossil Shells of the 

 genus Scaphites and Crepidula : with some observations on the Ferru- 

 ginous Sand, Plastic Clay, and Upper Marine Formations of the United 

 States. (Read June 17, 1828.) 



Jour. Acad. Nat. Sci. Phila., vol. vi, 1828, pp. 107-119. 



