I9I3.] ORTMANN— THE ALLEGHENIAN DIVIDE. 819 



gheny Valley (Antietani and Conodoguinet creeks in Maryland and 

 Pennsylvania, Shenandoah River in the Virginias), but it is rather 

 frequent in the Potomac and its tributaries in West Virginia, Mary- 

 land and Pennsylvania in the region of the Allegheny Mountains. 



IV. The Fauna of Rappahannock River. 



The Rappahannock is a Piedmont Plateau stream, and is entirely 

 east of the Blue Ridge. I collected near the headwaters about Rem- 

 ington, Fauquier Co., and Culpepper and Rapidan, Culpepper Co., 

 Va. The following is the list : 



List No. 20. 



1. Elliptio complanatus (Dillw.) 



2. Elliptio productus (Conr.) 



3. Elliptio lanceolatus (Lea) 



4. Symphynota tappaniana (Lea) 



5. Alasmidonta heterodon (Lea) 



6. Alasmidonta undidata (Say) 



7. Strophitus edentidus (Say) 



I give this list only for comparison ; probably it is not quite com- 

 plete. The interesting points are, that Alasmidonta heterodon turns 

 up here again, and that there is here a new, southern form, which 

 does not go farther north {Elliptio lanceolatus) . 



V. The Fauna of the Upper James River. 



I did not do any collecting in James River east of Blue Ridge, 

 and although a few records are at hand from the lower James, it 

 is impossible to give a complete list. West of Blue Ridge, the fauna 

 of North River (called Calf Pasture River in its upper part) has 

 been studied many years ago by Conrad (1846). I place his list by 

 the side of the forms collected by myself in this region : 



List No. 21. 



Conrad's list: Species collected by myself: 



Unio siihplanns Conr. =1. Lexingtonia siih plana (Conr.) 



Unio purpureus Say =2. Elliptio complanatus (Dillw.) 



PROC. AMER. PHIL. SOC, LII. 2IO C, PRINTED JULY II, I9I3. 



