46 THE PLIOCENE AND PLEISTOCENE DEPOSITS OF MARYLAND 



1871. 



Shaler, N. S. On the Causes which have led to the Production 

 of Cape Hatteras. 



Proc. Boston Soc. Nat. Hist., vol. xiv, 1871, pp. 110-121. 



He thinks that Delaware and Chesapeake hays were excavated hy streams or rivers 

 of ice and that the excavated material was deposited farther southward along the 

 coast and produced the sandy coast of Hatteras. 



1877. 



Eogers, Wm. B. On the Gravel and Cobble-stone Deposits of Vir- 

 ginia and the Middle States. 



(Read May 19, 1875.) Proc. Boston Soc. Nat. Hist, vol. xviii, 1877, pp. 

 101-106. 



The gravels and cohbles (of the Columbia and Lafayette) about Washington, Balti- 

 more, Richmond, Wilmington, etc., are described, and materials from the Potsdam and 

 other Paleozoic formations to the westward are recognized. These, he thinks, were 

 brought down by the present rivers when the land stood at a lower level and their 

 flooded headwaters extended into the region then glaciated. Thus he correlates the 

 deposits with the glacial deposits. 



1878. 



Stevenson, John J. On the Surface Geology of Southwest Penn- 

 sylvania, and adjoining portions of Maryland and West Virginia. 



Amer. Jour. Sci., 3d ser., vol. xv, 1878, pp. 245-250. 



He distinguished twenty horizontal benches and river terraces ranging in elevation 

 from 580-1100 feet above the sea, which he regards as " sea beaches marking stages of 

 the withdrawal of the ocean." No specific localities are given in Maryland. 



1879. 



Fontaine, W. M. Notes on the Mesozoic of Virginia. 



Amer. Jour. Sci., 3d ser., vol. xvii, 1879, pp. 25-39, 151-157, 229-239. 



Makes a few indefinite remarks in regard to gravels. 



1881. 



Lewis, H. C. On Jurassic Sand. 



Proc. Acad. Nat. Sci., Phila., vol. xxxii, 1881, p. 279. 



Recognizes Bryn Mawr gravels near Elkton. 



1S83. 



Cook, George H. The change of Eelative Level of the Ocean and 

 the Uplands of the Eastern Coast of North America. 



Proc. Amer. Assoc. Adv. Sci., vol. xxxi, 1883, pp. 400-408. 



A general paper with reasoning applicable to Maryland. Writer regards oscillation 

 connected with ice movements as the principle factor. 



