298 ORTMANN— THE ALLEGHENIAN DIVIDE. [April i8. 



The similarity of this fauna to that of the uppermost Allegheny- 

 is evident. Eight forms are in either list, seven of which are found 

 in both. 



Crooked Creek has its fauna fully preserved. I collected in both 

 the lower and upper part. In the lower part, in Armstrong Co., 

 near its confluence with the Allegheny, the following are found. 



List No. ya. 



1. Fusconaia undata ruhiginosa (Lea) 



2. Crenodonta plicata undulata (Barn.) 



3. Pleurohema obliqiium coccineum (Conr.) 



4. Elliptio dilatatus (Raf.) 



5. Symphynota costata (Raf.) 



6. Anodonta grandis Say 



7. Alasmidonta marginata (Say) 



8. Strophitus edentulus (Say) 



9. Ohovaria circulus lens (Lea) 



10. Nephronaias ligamentina (Lam.) 



11. Eurynia fahalis (Lea) 



12. Eurynia iris (Lea) 



13. Eurynia recta (Lam.) 



14. Lampsilis luteola (Lam.) 



15. Lampsilis ovata ventricosa (Barn.) 



16. Lampsilis multiradiata (Lea) 



17. Truncilla triquetra Raf. 



This is a depauperated lower Allegheny fauna, with the addition 

 of a few species (nos. 6, 11, 12) which are characteristic for smaller 

 streams. 



In the upper part of Crooked Creek, in Indiana Co., there are: 



List No. yb. 



1. Fusconaia undata ruhiginosa (Lea) 



2. Symphynota costata (Raf.) 



3. Anodonta grandis Say 



4. Strophitus edentulus (Say) 



