CRETACEOUS FOSSILS. 143 



anterior end of the month ; at the extremity is a prominent 

 fold, and a short distance above it another one, somewhat larger 

 and sharper. 



Length, .53 inch; width, .28 inch. 



Locality: Common on the north fork of Cottonwood Creek. Collected by 

 Messrs. Brewer and Esmond. 



BULLA, Klein, Brug. 



B. Hornii, 11. s. 



PL 29, Fig. 235. 



Shell moderate in size, thin, ovoid, most prominent about 

 one-third of the length from the upper end, the sides gradually 

 curving downwards and approaching to near the anterior end, 

 when they curve rapidly inwards ; summit umbilicated. Mouth 

 broad, the upper end projecting a short distance above the pre- 

 ceding whorl, and regularly rounded; anterior end broad, pro- 

 duced; outer lip simple, thin; inner lip unknown, apparently 

 not in crusted, covered in such a manner by the matrix, espe- 

 cially in advance, as to hide the characters. Surface marked by 

 numerous, very fine, impressed, revolving lines. 



Figure, slightly magnified. 



Locality: A single specimen was found by Dr. Horn, near Fort Tejon. 



The shorter and more convex outline will serve to distinguish this species from 

 Cylichna costata, which is also found at the same locality. A further difference is 

 to be found in the sculpture, the lines, in this species, being much further apart 

 than in the other ; the shell is also much thinner. 



I take great pleasure in dedicating this species to the discoverer, to whom I am 

 indebted for many fine specimens, not a small portion of which were new to me. 



CYLICHNA, Loven. 



C. COSTATA, 11. S. 

 PL 21, Fig. 107. 



Shell elongated, subcylindrical, widest anteriorly; spire hid- 

 den ; whorls (from casts) three or four. Surface marked by very 



