114 THE GEOLOGY OF CALVERT COUNTY 



overlies the Raritan formation unconformably, and is itself abruptly 

 buried beneath Talbot sands and gravel. 



Another locality is on the Bay shore, about a mile northeast of Drum 

 Point. Here, at the base of a cliff about 30 feet high, is a 2-foot bed 

 of dark, chocolate-colored clay carrying gnarled and twisted sticks pro- 

 truding in every direction from the material in which they are imbedded. 

 Above this occurs a thin seam of lignite 1^ feet thick, which in turn is 

 overlain with about 5 feet of slate-colored clay. At this point the con- 

 tinuity of the deposit is interrupted by a series of sands, clays, and 

 gravels belonging to the Talbot formation, which extend upward to the 

 top of the cliff. Although the base of this lignitic clay series is buried 

 beneath beach sands, field relations lead to the conclusion that the de- 

 posit is very much younger than the Miocene clays on which it rests un- 

 conformably. A similar section is to be seen on the Patuxent Eiver, 

 about a mile below Sollers Landing. Large stumps here protrude from 

 a dark, basal clay bed, some 5 feet in thickness, which is covered by 3 

 feet of sand, and this again is buried beneath 10 feet of Talbot sand 

 and gravel. The relations of the basal clay to the underlying Miocene 

 is again obscure, but indications point to an unconformity. Another 

 section is exposed along the shore 1^ miles northwest of Cedar Point, 

 where a thin bed of drab clay carrying vegetable remains is overlain 

 abruptly with sands and gravels. Its contact with the Miocene is again 

 unfortunately obscure. At the localities just described no animal re- 

 mains have been discovered, but on the north bank of the Potomac, about 

 half way between St. Mary's River and Breton Bay, there is a deposit of 

 lead-colored clay, exposed for a quarter of a mile along the shore. It is 

 buried at each end as well as above by sands and gravels and carries both 

 lignite and Rangia cuneata (Conrad). Although the description given 

 by Conrad is somewhat vague, it is highly probable that he visited this 

 locality and collected specimens of the fossils. Two more localities 

 still remain to be mentioned. Cornfield Harbor, and its companion de- 

 posit exposed 5^ miles south of Cedar Point on the Bay shore. Conrad 

 was well acquainted with these deposits and to the former he devoted 

 special attention. Each is about 10 feet thick, occurs at the base of a 



