MARYLAXD GEOLOGICAL SURVEY 35 



1820. 

 Hayden^ Horace H. Geological Essays ; or An Inquiry into some 

 of the Geological Phenomena to be found in various parts of America, 

 and elsewhere. 8vo, 412 pp. Baltimore, 1820. 



The writer contends that the unconsolidg,ted deposits bordering the Atlantic 

 Ocean are not alluvial materials, but have been brought to their present posi- 

 tion by an ocean current which swept over the eastern part of the country 

 in a southwesterly direction. The rise of the ocean is believed to have been 

 caused by an increase of water due to the melting of the polar ice produced 

 by a shifting of the earth's axis. 



1824. 



FiNCH^ John. Geological Essay on thfe Tertiary Formations in 

 America. (Read before Acad. ^at. Sci., Phila., July 15, 1823.) 



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



Objection is made to the term "alluvial formation" of Maclure and others 

 on the ground that the deposits are for the most part not of alluvial origin, 

 and also that, as used, it includes a number of distinct formations that can 

 be correlated with the "newer secondary and tertiary formations of France, 

 England, Spain, Germany, Italy, Hungary, Poland, Iceland, Egypt, and Hindoo- 

 stan." The writer makes some provisional correlations which are now known 

 to be wrong. He admits, however, that the data are insufficient for accurate 

 correlation. The clay which is found beneath the 54 feet of "diluvial gravel" 

 on Capitol Hill, Washington, and which contains remains of trees is consid- 

 ered by him the equivalent of the London clay. 



1826. 



Pierce, James. Practical remarks on the shell marl region of the 

 eastern parts of Virginia and Maryland, and upon the bituminous 

 coal formation in Virginia and the contiguous region ; extracted from 

 a letter to the Editor Amer. Jour. Sci., vol. xi, pp. 54-59, 1820. 



Mentions the occurrence of shell marl of marine origin in the "alluvial" 

 district of Maryland on both sides of Chesapeake Bay, and discusses its value 

 as a fertilizer in the renovation of exhausted soils. Refers specifically to the 

 calcareous-cemented beds of shells at "Marlborough" (Upper Marlboro) and 

 other places west of Chesapeake Bay. He states that the shell marl extends 

 up the Potomac river to within S miles of Washington. 



