upper Ordovician at Vevay, Ind. — Ciunings. 369 
The remainder of the Platystrophia beds is, as stated above, 
from the exposures along the road a short distance from the 
upper exposures of the section just described. The zone which 
h here 40 to 50 feet thick is divided arbitrarily into eight 
equal sub-zones for the purposes of analysis of the faunas. 
These sub-zones are lettered a to h from the base up. Litho- 
logically they vary but little, there being somewhat more sandy 
material in the lower layers and a greater percent, of argilla- 
ceous material further up in the section. All the layers are 
very thin and irregular and easily disintegrated constituting 
on the whole an extremely shaly limestone. 
The faunas of these sub-zones are as follows : 
Zone A : 
1. Homotrypa curvata Ulrich (aa). 
2. Ceramoporella oliioensis (Nicholson). 
3. Peronopora decipiens (Rominger). 
4. Dekayia sp. 
5. Heterotrypa inilecta Ulrich. 
6. Dekayia aspera E. & H. 
7. Callopora suhplana Ulrich. 
8. Callopora rugosa (E. & H.). ? 
9. Bythopora sp. 
10. Escharopora pavonia (d'Orbigny). 
11. Escharopora falciformis (Nicholson). 
12. Platystrophia biforata-lynx (Eichwald). 
13. Platystropliia biforata-dcntata Meek. 
14. Raftnesqiiina alternata (Con.). 
15. Plectorthis plicatella Hall. 
16. Hebertella occidentalis-sinuata Hall. 
17. Acidaspis sp. 
18. Heterocriniis sp. 
19. Cyclora viintita Hall. 
Zone B : 
1. Ceramoporella ohiocnsis (Nicholson) (c). 
2. Bythopora delicatula (Nicholson). 
3. Callopora rugosa (E. & H.). 
4. Escharopora pavonia (d'Orbigny). 
5. Monticulipora mammulata (d'Orbigny). 
6. Escharopora falciformis (Nicholson). 
7. Constellaria constellata (Van Cleve) Dana. 
8. Petigopora aspernla Ulrich. 
9. Rafinesquina alternata (Con.) typical (a). 
10. Zygospira modes ta Hall (a) 
11. Hebertella occidentalis-sinuata Hall (c). 
12. Plectorthis plicatella Hall. 
