Igo UNIVERSITY OF COLORADO STUDIES 
Cardium speciosum M. and H. 
Abundant at Fossil Ridge and Rocky Ridge. We have not found it elsewhere below 
the upper Pierre, but it is abundant throughout the Fox Hills formation from Boulder 
Creek to the Cache la Poudre. Found in Eagle and Claggett formations, equivalent to 
lower Pierre (Stanton MSS, reported by Meek as Fox Hills) on the Judith River, Montana. 
Callista deweyi M. and H. 
Common at Fossil Ridge and Rocky Ridge. We have found a number immediately 
above the Hygiene sandstone three miles north of Boulder. In the Denver Basin mono- 
graph it is credited to Fox Hills strata. In a former paper [University of Colorado Studies, 
Vol. II, p. 104] the writer listed this species from Fossil Ridge as Lucina, by a curious over- 
sight. It is found on the Yellowstone River in strata containing a blending of upper 
Pierre and Fox Hills fossils (Meek). 
Tellina scitula M. and H. 
We have a single valve from Fossil Ridge, a species we have found in the Fox Hills 
sandstone at every exposure examined from the Denver Basin to the Cache la Poudre. 
It is recorded from Fox Hills strata also in the Upper Missouri region (Meek), and Dr. 
Stanton (MSS) reports it from low in the Pierre elsewhere. 
Mactra sp. 
A small specimen not specifically determinable, probably juvenile, we found on 
Fossil Ridge seven miles south of Ft. Collins. 
Teredo ? sp. 
Fossil wood is found on Fossil Ridge containing casts of borings resembling those of 
Teredo or Parapholas. 
GASTEROPODA 
Margarita nebrascensis M. and H. 
Abundant at two or three places along Fossil Ridge. We are not aware of its occur- 
rence elsewhere in Colorado. Found on the Yellowstone River in Pierre and Fox Hills 
strata (Meek). 
Capulus n. sp. 
Fossil Ridge is the only locality in which we have found this species, and only two 
adults and one juvenile were found. 
Gyrodes abyssina Morton 
A single specimen of this species from Fossil Ridge was heretofore recorded as 
Lunatia sp., but Professor R. P. Whitfield has since shown its identity with the New Jersey 
species. Like Gyrodes crenata Conrad, it is found in the Lower Marls of New Jersey, 
forming additional threads in the strand of evidence connecting those beds with the Pierre 
shales in point of time. [Whitfield, U.S. Geol. Sur., Mon., Vol. XVIII, pp. 32, 123, 125; 
Weller, Geol. Sur. of New Jersey, Paleontology, Vol. IV, pp. 683-685.] 
Gyrodes crenata Conrad 
We have a single specimen found at Fossil Ridge. Identified by Professor R. P. 
Whitfield as G. infracarinata Gabb, which appears equivalent to Conrad’s species. [Weller, 
Geol. Sur. N. J., Paleontology, Vol. IV, pp. 685-686.] As to its occurrence elsewhere, 
see Gyrodes abyssina. 
