MARYLAND GEOLOGICAL SUEVEY 25 



United States. In this publication the coastal deposits of the Middle 

 Atlantic Slope are collectively referred to the " Alluvial formation," the 

 fourth of the main divisions of geological strata originally proposed by 

 Werner. The work Avas subsequently revised and enlarged, appearing in 

 book form in 1817. 



In 1820 H. H. Hayden, of Baltimore, published a volume of G-eological 

 Essays, in which he attempted to explain the great accumulation of 

 "alluvial deposits" in the Atlantic Coastal Plain. In this volume the 

 stratigraphy of the region is described in much greater detail than by 

 his predecessors, and reference is made to the wide distribution of fossil 

 shells and vertebrate remains, many localities being cited. 



A volume of the same character, so far as it relates to the geology, was 

 published in 1822 by Parker Cleaveland, entitled an Elementary Trea- 

 tise on Mineralogy and Geology, in which, on page 785, under remarks 

 on the " Geology of the United States explanatory of the subjoined 

 geological map," the limits and the lithological character of the " allu- 

 vial deposits " are described in general terms. 



By far the most imj)ortant contribution to the stratigraphy of the 

 Atlantic Coastal Plain that had up to that time appeared was made by 

 Professor John Finch, in a " Geological essay on the Tertiary formations 

 in America," in the American Journal of Science and Arts for 1824. 

 This was the first attempt at a division of the deposits of the Coastal 

 Plain and their correlation upon scientific grounds; and although thus 

 early in the history of the subject detailed comparisons (which are 

 always unsatisfactory) were made, yet the knowledge of the formations 

 was materially advanced. The author says: 



In America an immense tract of country, extending from Long Island to the Sea 

 of Mexico, and from 30 to 200 miles in width, is called an alluvial formation. From 

 an examination of fossils brought from that quarter of the United States, from a 

 personal inspection of some of its strata, and the perusal of most of the publications 

 which bear a reference to it, I wish to suggest that what is termed the alluYial for- 

 mation in the geological maps of Messrs. Maclure and Cleaveland is identical and con- 

 temporaneous with the newer Secondary and Tertiary formations of France, England, 

 Spain, Germany, Italy, Hungary, Poland, Iceland, Egypt and Hindostan. 



The deposits of various portions of the Middle Atlantic Slope are 

 considered in greater or less detail, and correlations with the strata of 



