308 ORTMANN— THE ALLEGHENIAN DIVIDE. [April i8, 



and in Reed Creek, Wytheville, Wythe Co., Va. Three species only 

 are present here : 



List No. 14. 



1. Elliptic* dilatatus (Raf.) 



2. Symphynota tappaniana (Lea) 



3. Alasmidonta marginata (Say) 



At Pearisburg I did not find no. 3, but at the other localities all 

 three were present. In addition, Elliptio dilatatus has been reported 

 by Call ('85, p. 30) from Bluestone River (tributary to New River, 

 emptying into it just above Hinton). 4 



These conditions correspond closely to what we have observed 

 in the case of the mountain streams tributary to the Monongahela. 

 There is a rough part in the river in the shape of a canyon. Below 

 the canyon the fauna is rich, above it is extremely poor. In the 

 present case two species {Quadrula tuberculata and Rotundaria 

 tuberculata) have gone up through the lower part of the canyon, but 

 they were unable to go farther, and the uppermost parts of the New 

 River system, where conditions undoubtedly are favorable for 

 Najades, contain only three species, two of which belong to the 

 Ohio fauna, while the third is a complete stranger. With the ex- 

 ception of this case, which will be further discussed below, the 

 whole Kanawha fauna, including that of New River, is undistin- 

 guishable from the general upper Ohio fauna. But it should be 

 noted that the species found in the headwaters of the Kanawha are 

 different from those found in the headwaters of the mountain tribu- 

 taries of the Monongahela. 



VI. Big Sandy and Licking Rivers. 



South of the headwaters of New River, in the Greater Allegheny 

 Valley, we strike the headwaters of the Tennessee drainage, Holston, 



4 Bluestone River is now badly polluted. I have seen it in its upper part, 

 at Rock, Mercer Co., W. Va. Call {ibid., p. 55) already gives Rotundaria 

 tuberculata (as Unio verrucosus Barn.) from New River, Virginia: but' 

 according to my investigations, this is only in the New River in West Virginia 

 (at Hinton). Call also says Bluestone River, Virginia, but only the extreme 

 headwaters are in Virginia, the rest in West Virginia. 



