38 THE PHYSICAL FEATUKES OF CALVERT COUNTT 



but the relation which existed between them was not understood and 

 little attention was given to the matter. To go into a full discussion of 

 the history of this separation would be to repeat much that has already 

 been said. Those who desire to look into the early history in more detail 

 are referred to the Eeport on the Pliocene and Pleistocene of Maryland, 

 Maryland Geological Survey, 1906. It was not until Professor W J 

 McGee published his investigations of these deposits in 1887 and 1888 

 that their true relation with the underlying formations was at all under- 

 stood. He gave the name of Columbia formation to this entire series 

 of deposits and divided them into fluviatile and interfiuviatile phases 

 which he considered contemporaneous. Later, Darton, who took up the 

 work where McGee left it, divided the Columbia formation of McGee 

 into an Earlier and a Later Columbia. In 1901, Shattuck, who had 

 studied the region in still more detail, separated the same deposits into 

 three formations, the Sunderland, Wicomico, and Talbot, which he united 

 under the general term Columbia Group. He also showed that these 

 were developed in terraces lying one above the other in order of their 

 age, the oldest lying topographically highest. The same year, J. A. 

 Bonsteel and P. T. Avon Burke published a report on the soils of 

 Calvert County. 



The next year Shattuck published a report on Cecil County in which 

 he referred to the lignite deposits of Calvert County and suggested an 

 explanation of their origin. In 1904 the Miocene deposits of Maryland 

 were fully described by Clark, Shattuck, Dall, Glenn, Martin, and 

 others. In this report a geologic map, sections and many photographs 

 were published. The same year the St. Mary's ^P'olio, by Shattuck and 

 Miller, was published by the U. S. Geological Survey. This contained a 

 summary of the geology of the county and a geologic map of its south- 

 ern portion. Clark and Mathews also published a summary of the physi- 

 cal features and geology of Maryland in which Calvert County was given 

 considerable attention. Before the close of the year the report on the 

 Pliocene and Pleistocene deposits of Maryland appeared under the author- 

 ship of Clark, Shattuck, Hollick, Lucas, and others. In this report the 

 surficial deposits of Calvert County are discussed at great length. 



