I9I3-] ORTMANN— THE ALLEGHENIAN DIVIDE. 297 



List No. 5. 



(Those marked * are from the Allegheny, those marked f from 



Potato Creek.) 



*l. Pleurobema obliquum coc ein earn (Conr.) 

 *f2. Elliptio dilatatus (Raf.) 



f3. Symphynota compressa Lea 

 *fzj.. Symphynota costata (Raf.) 



*5. Alasmidonta marginata (Say) 



f6. Strophitus edentnlus (Say) 

 *f7. Lampsilis luteola (Lam.) 



*8. Lampsilis ovata ventricosa (Barn.) 



The number of forms again has been greatly reduced in com- 

 parison with list no. 4. All species found here are also found farther 

 below, and thus this fauna is simply depauperated. 



I collected also in the uppermost Allegheny above Coudersport, 

 Potter Co., but here this is a mere run, and has no Najades. (Im- 

 mediately below Coudersport it is polluted.) 



We come now to the eastern tributaries of the Allegheny River, 

 running down from the divide in a general east-west direction. 

 They are (from north to south) : Clarion River, Red Bank River, 

 Mahoning Creek, Crooked Creek, and Kiskiminetas River. The 

 first two are entirely polluted, and no shells are known from them. 

 The same is true for Mahoning Creek, from Punxsutawney down. 

 But in northern Indiana Co. there is a tributary of the latter, Little 

 Mahoning Creek, where I collected the following shells : 



List No. 6. 



1. Pleurobema obliquum coccineum (Conr.) 



2. Elliptio dilatatus (Raf.) 



3. Symphynota costata (Raf.) 



4. Alasmidonta marginata (Say) 



5. Strophitus edentulus (Say) 



6. Ptychobranchus phase olus (Hildr.) 



7. Lampsilis luteola (Lam.) 



8. Lampsilis ovata ventricosa (Barn.) 



