1 
Thespesius occidentalis, Leidy. 
Ischyrotherium antiquum, * 
Compsemys victus, 
Emys obscurus, 
Cyclus formosa, Meek and Hayden. Proc. Acad. Nat. Sci., Pa., VIII.. p. 
Cyclas fragilis, 
Cyclas subellipticus, 
Cyrena moreauensis, 
Cyrena intermedia, 
Corbula mactriformis, 
Unio priscus, 
Bulimus teres, 
Bulimus vermiculus, 
Bulimus limneaformis, 
Bulimus nebrascensis, 
Pupa helicoides, 
Limnea tenuicosta, 
Physa longiuscula, 
Physa nebrascensis, 
Planorbis subumbilicatus, 
Planorbis convolutus, 
Planorbis fragilis, 
Velletia (Ancylus) minuta, 
Paludina multilineata, 
Paludina Leai, 
Paludina retusa, 
Paludina peculiaris, 
Paludina trochiformis; 
Paludina Leidyi, 
Valvata parvula, 
Melunia minutula, 
Melania Anthonyi, 
Melania multistriata, 
Melania nebrascensis, 
Melania Warrenana, 
36 GEOLOGICAL SKETCH 
(73 
OF THE ESTUARY AND FRESH WATER DEPOSIT 
VERTEBRATA. 
Proc. Acad. Nat. Sci., Pa, VIII. p. 
66 
66 
66 
MOLLUSCA. 
66 
(15 
oe 
ce 
66 
(13 
(75 
66 
66 
(15 
it 
89. 
312. 
312. 
(3%) 
115. 
Gy, 
nie 
118. 
L19F 
120. 
120. 
121. 
122. 
123. 
124. 
