50 Trans. Acad. Sci. of St. Louis. 
Trenton Period 
Stones River 
Group 
Black River 
Group 
Group 
Trenton 
Cincinnati Region 
Tennessee Region 
New York Region 
Canada Region 
PoRIFERA, CORLENTERATA 
AND BRYOZOA 
Hindia parva? Ulrich.......... 
Streptelasma corniculum? Hall... 
Lichenaria typa? W.and §8..... 
Rhinodictya sp. undet........... 
BRACHIOPODA 
Dalmanella subaequata Conrad .. . 
Dalmanella testudinaria Dalman.. 
Lingula sp. undet.............. 
Orthis tricenaria Conrad......... 
Strophomena incurvata Sheppard. 
Zygospira recurvirostra Hall...... 
Zygospira nicolleti W. and §..... 
PELECYPODA 
Ctenodonta auburnensis n. sp..... 
Ctenodonta costata n. sp.......... 
Ctenodonta medialis Ulrich....... 
Ctenodonta nasuta Hall.......... 
Ctenodonta oviformis Ulrich...... 
Cienndenta 0. 8B .5 Fe Vo ea 
Cyrtodonta billingst Ulrich....... 
Cyrtodonta sp. undet............ 
Goniophora carinata Conrad...... 
Modiolodon subrhomboideus n. sp. 
Modiolopsis expansa nN. Sp....... 
Modiolopsis sp. undet........... 
Parallelodus obliquusn. gen. and sp. 
Psiloconcha? sp. undet .......... 
Rhytima sp. undet............+. 
Sphenolium sp. undet........... 
Whiteavesia subcarinata Ulrich... . 
GASTRC PODA 
Archinacella patelliformis Hall. ... 
Archinacella sp. undet........... 
Carinaropsis actua U. and §...... 
Carinaropsis phaleria Sardeson.. .. 
Cataschisma typa n. gen. and sp.. 
Conradella fimbriata U. and 8.... 
Cyrtolites retrorsus Ulrich........ 
xXxXX XxX 
x X 
xX X 
xX 
Bw 
TU 
SB 
st 
SB 
BtoH 
BT 
BT 
BT 
BT 
