I9I3.] ORTMANN— THE ALLEGHENIAN DIVIDE. 297 



List No. 5. 



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



Potato Creek.) 



*i. Pleitrobenia obliquiiiii cocciiieiun (Conr.) 



*t2. Elliptio dilatatus (Raf.) 



f3. Symphynota compressa Lea 



*f4. Symphynota costata (Raf.) 



*5. Alasmidonta marginata (Say) 



f6. Strophitns edentnlns (Say) 



*f7. Laiiipsilis luteola (Lam.) 



*8. Lampsilis ovata zrutricosa (Barn.) 



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

 parison with Hst 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. Pleurohema obliqnum coccinenm (Conr.) 



2. Elliptio dilatatus (Raf.) 



3. Symphynota costata (Raf.) 



4. Alasmidonta marginata (Say) 



5. Strophitns edentnlus (Say) 



6. Ptychobranchus phaseohis (Hildr.) 



7. Lampsilis luteola (Lam.) 



8. Lampsilis ovata vcntricosa (Barn.) 



