MAE YL AND GEOLOGICAL SURVEY 37 



trinsic problem of the Piedmont rocks presented difficulties too great 

 to be overcome, and attention was consequently directed to unravel- 

 ling the stratigraphy of the Coastal Plain. Of the large number of 

 papers which have been published since investigation commenced in 

 Cecil county, only a very few are of sufficient importance to deserve 

 mention in this review. 



The first paper of importance was published by William Maclure 

 in 1809. Although this contribution dealt in a broad way with the 

 geology of the United States, yet it shed considerable light on Cecil 

 county. Maclure separated the formations of that region into two 

 great provinces, the Primitive and the Alluvial. These two divisions 

 corresponded to what we now know as the rocks of the Piedmont 

 Plateau and the deposits of the Coastal Plain, and the line which 

 separated the two groups was drawn by Maclure approximately as it 

 is known to-day. This paper, which was accompanied by a geological 

 map, was republished many times in subsequent years; the last one 

 appearing in 1826. The unity of the Coastal Plain deposits as pro- 

 mulgated by Maclure seems to have been quite generally accepted at 

 the time, for Hayden, in 1820, in a series of essays which attracted 

 considerable attention, referred to these Alluvial deposits and 

 advanced the theory that they were deposited not by rivers but were 

 swept in by a great flood which crossed North America from north- 

 east to southwest. Two years later, Parker Cleaveland endorsed 

 Maclure's map by reproducing it in his treatise on mineralogy. 



No serious exception seems to have been made to Maclure's inter- 

 pretation until 1824, when Professor John Pinch, an Englishman who 

 was making a tour of the United States, called attention to the com- 

 plex character of the Alluvium. He divided it into Ferruginous sand 

 and Plastic clay, and correlated these with the Newer Secondary and 

 Tertiary of Europe, Iceland, Egypt and Hindustan. His correlations 

 were made largely on lithologic distinctions and on a general like- 

 ness of fossil forms without a close or minute comparison of either. 

 Of more significance, however, was his statement that future work 

 would show some eight or ten formations between the Alleghany 



