26 THE PLIOCENE AND PLEISTOCENE DEPOSITS OF MARYLAND 



the means and time at his disposal. This map was employed by ex- 

 plorers and colonists for many years, and although the earliest, was 

 superior to many other maps which appeared later. 



Almost one hundred years elapsed after the publication of Smith's 

 narrative before naturalists turned their attention toward the deposits of 

 the Coastal Plain. This long delay in studying the geology of tide- 

 water Maryland was doubtless due to the lack of precious metals through- 

 out the region as well as to the great difficulty encountered in thoroughly 

 exploring a country which was only partially settled. When interest 

 was finally aroused, it centered about the deposits of iron-bearing clays 

 on the one hand and the fossil-bearing marls on the other, so that the 

 surficial cover of gravel and sand was either erroneously interpreted or 

 neglected altogether. Of all the Coastal Plain deposits it has been the 

 last to receive minute systematic study. 



After the publication of Smith's narrative, the first paper to appear 

 bearing on the geology of the Coastal Plain was by Silvain Godon in 

 1809. When he made this contribution, none of the various Coastal 

 Plain formations had been recognized, but all the unconsolidated 

 materials lying between the eastern margin of the Piedmont Plateau 

 on the west and the Atlantic Ocean on the east were thought to belong 

 to one great deposit. This Godon called " alluvion soil," applying his 

 description to that portion of the Coastal Plain which lies between 

 Baltimore and Washington. He further said that " Washington City is 

 built on alluvial land." 



In the same year William Maclure published a paper which may be 

 considered as truly classic. His studies embraced a wider sphere of 

 observation than did those of his predecessor, for in the colored geological 

 map which accompanies his publication he includes all the eastern por- 

 tion of the United States. The great major divisions, such as the uncon- 

 solidated deposits of the Coastal Plain, the crystalline rocks of the 

 Piedmont Plateau, and the folded sedimentaries of the Appalachian 

 mountain system, are recognized on his map, but the individual forma- 

 tions which make up these various physiographic regions are not 

 recognized in much detail. In treating of the Coastal Plain, he has not 



