f 



WHTTB.] FOSSILS OF THE FOX HILLS GROUP. 183 



Fossil Eidge, where I discovered it; which strata, although not sepa- 

 rable from the Fox Hills Group in Colorado, are no doubt equivalent 

 witli those of the Fort Pierre Group in the Upper IMissouri Eiver region. 

 1 obtained it in considerable numbers from the liigher strata of the Fox 

 Hills Group at the mouth of the Saint Yraiiis and in the valleys of tlie 

 ( 'ache a la Poudre and Little Thomi)son Cieek. JSouie well i)reserved 

 l)ieces of the test of this species obtained at Fossil Eidge show that 

 what appear to be nodes between tlie ribs in certain si^ecimens are in 

 the unchanged shell really holes through its substance. The pieces 

 referred to were found to break along the line of these holes, just as post- 

 age-stamps separate along the lines of holes made for that purpose. In 

 other examples from the valley of the Caclie a la Poudre I found the 

 api)earance of nodes in the place of the holes, just as described by Mr. 

 Meek ; but careful examination showed that the supposed nodes consist 

 of the stony tilling of the holes in the test, which, being harder, had 

 withstood subsequent weathering better than the test itself. It is pos- 

 sible, however, that the outer end of these holes was covered mth a 

 shelly layer ; but it must have been oidy a iilm at most, for I could dis- 

 cover nothing of the kind in the narrow grooves between the ribs of the 

 specimens referred to, which seemed to be perfectly i^reserved. 



19. Frotocardia sitbquadrata Evans & Shumard sp. 



Dr. Evans first discovered this species in the Fox Hills Group of the 

 Upper Missomi Eiver region. I obtained it in the valley of the Little 

 Thompson; and I have also recognized it in some collee'sons made by 

 Mr. W. H. Holmes at the mouth of the Saint Vrains. It seems never 

 to have been discovered in the Fort Pierre Group of the Upper Mis- 

 somi. 



20. Protocardia rara Evans & Shumard. 



Associated with the foregoing in the valley of the Little Thompson, I 

 found some small shells that seem to belong to this si>ecies, but their 

 identification was not quite satisfactory. 



21. CalUsta deioeyi Meek & Hayden. 



A few imperfect examples, found both at Fossil Eidge and in the val- 

 ley of Little Thompson Creek, evidently belong to the Dosinoims section 

 of this genus. They .are too imperfect for certain specific determination, 

 but the character of the internal cast and what remains of the shell in- 

 dicates a proper reference to C. deweyi. 



22. Tellina scitida Meek & Hayden. 



This is a very common and widely distributed Cretaceous species, being 

 found on both sides of the Eocky Mountains. It seems, however, to be 

 confined everywhere to the strata of the Fox Hills Group. . In this dis- 

 tinct 1 obtained it only from the uj^per strata of that gi'oup, and only at 

 the mouth of the Saint Vrains and in the valley of the Cache a la Pou- 

 dre. 



23. Tellina eqiiilateralis Meek & Hayden. 



A single valve of a species, apparently the T. equiJateralis of Meek and. 

 Hayden, was found at the mouth of the Saint Vrains. The original ex-- 

 amples were found in the uppermost of the h^ox Hills layers at the mouth: 

 of Judith Eiver on the Upi)er Missouri. Meek referred the species to- 

 Tellina from external characters onlj^, and there are reasons for believ- 

 ing that it does not properly belong to that genus. 



