386 ORTMANN— THE ALLEGHENIAN DIVIDE. [April 1 8, 



Maury, M. F., and Fontaine, W. M. 



1876. Resources of West Virginia. State Board of Centennial Managers, 

 1876. 

 McGee, W J 



1888. Three Formations of the Middle Atlantic Slope. Amer. Journ. Sei. 

 (3), 35, 1888, pp. 120-143. 

 Ortmann, A. E. 



1905. The Mutual Affinities of the Species of the Genus Cambarus, and 

 their Dispersal over the United States. Pr. Amer. Philos. Soc, 44, 

 1905, PP. 92-136. 



Ortmann, A. E. 



1906. The Crawfishes of the State of Pennsylvania. Mem. Carnegie Mus., 

 2, 1906, pp. 343-524. 



Ortmann, A. E. 



1912a. Notes upon the Families and Genera of the Najades. Ann. Carne- 

 gie Mus., 8, 1912, pp. 222-365. 

 Ortmann, A. E. 



1912b. Lampsilis ventricosa in the Upper Potomac Drainage. Nautilus, 26, 

 1912, pp. 51-54. 

 Pilsbry, H. A. 



1894. Critical List of Mollusks Collected in the Potomac Valley. Pr. 

 Acad. Philad., 1894, pp. 11-30. 



Powell, J. W. 



1896. Physiographic Regions of the United States. The Physiography of 

 the United States. Nation. Geogr. Soc, 1896, pp. 65-100. 

 Rhoads, S. N. 



1904. A Glimpse at the Shell Fauna of Delaware. Nautilus, 18, 1904, pp. 



63-67. 

 Rogers, W. B. 



1884. A Reprint of Annual Reports and other Papers on the Geology of 



the Virginias. New York, 1884. 

 Schick, M. ♦ 



1895. Mollusk Fauna of Philadelphia and Environs. Nautilus, 8, 1895, pp. 

 133-140. 



Simpson, C. T. 



1893. On the Relationship and Distribution of the North American Union- 

 idae, with Notes on the West Coast Species. Amer. Natural., 27, 



1893, PP. 353-358. 

 Simpson, C. T. 

 1896a. On the Mississippi Valley Unionidse found in the St. Lawrence and 

 Atlantic Drainage Areas. Amer. Natural., 30, 1896, pp. 379-384- 

 Simpson, C. T. 



1896b. The Classification and Geographical Distribution of the Pearly 

 Freshwater Mussels. Pr. U. S. Mus., 18, 1896, pp. 295-343. 

 Simpson, C. T. 

 1900a. Synopsis of the Najades or Pearly Freshwater Mussels. Pr. U. S. 

 Mus., 22, 1900, pp. 501-1044. 



