I9I3-] ORTMAXX— THE ALLEGHEXIAX DIVIDE. 387 



Simpson, C. T. 



1900b. On the Evidence of the Unionidse Regarding the Former Courses 

 of the Tennessee and other Southern Rivers. Science, 12, July 27, 

 1900, pp. 133-136. 

 Spencer, J. W. 



1903. Submarine Valleys off the American Coast and in the North At- 

 lantic. Bull. Geol. Soc. Amer., 14, 1903, pp. 207-226. 



Stevenson, J. J. 



1887. A geological Reconnaissance of Bland. Giles, Wythe, and Portion 

 of Pulaski and Montgomery Counties of Virginia. Pr. Amer. Philos. 

 Soc, 24, 1887, pp. 61-108. 

 Tryon, G. W., Jr. 



1865-66. Monograph of the Family Strepomatidas. Amer. Journ. Conchol., 

 1, 1865, pp. 299-341; 2, 1866, pp. 14-52, 115-133. 

 U. S. Geological Survey. 



Topographical Atlas Sheets (as far as published). 

 Walker, B. 



1910. Distribution of Margaritana margaritifera in X T orth America. Pr. 

 Malacol. Soc. London, 9, 1910, pp. 126-145. 

 White, C. H. 



1904. The Appalachian River versus a Tertiary Trans-Appalachian River 

 in Eastern Tennessee. Journ. Geology, 12, 1904, pp. 34-39. 



White, I. C. 



1896. Origin of the High Terrace Deposits of the Monongahela River. 

 Amer. Geologist, 18, 1896, 368-379. 

 Willis, B. 



1896. The Northern Appalachians. The Physiography of the United 

 States. Nation. Geogr. Soc, 1896, pp. 169-202. 

 Willis, B. 



1912. Index to the Stratigraphy of North America, Accompanied by a 

 Geological Map of North America. U. S. Geol. Surv. Prof. Pap., 

 71, 1912. 



Carnegie Museum, 

 Pittsburgh, Pa., 

 April 18, 1913. 



