white.] CEOW CREEK FOSSILS. 169 



at that locality, and was obtained only from No. 3 of the section. It is 

 described in the Bulletin of the Geological and Geographical Survey of 

 the Territories, vol. iv, p. 711. 



No. S. Corbicula dbesa White. 



This species has been discovered both in Crow Creek and Bijou Creek 

 valleys, but not elsewhere. It comes from No. 3 of the Crow Creel; sec- 

 tion. It is described in the Bulletin of the Geological and Geographical 

 Survey of the Territories, vol. iv, p. 712. 



No. 9. Corbicula cardmusformis White. 



This is a rare but well-marked species. It was found only in bed No. 

 3 of the Crow Creek section, and is described in the Bulletin of the 

 Geological and Geographical Survey of the Territories, vol. iv, p. 711. 



No. 10. Corbicula (Leptesthes) subelliptica Meek & Hayden. 



Dr. Hayden originally discovered this species in the valley of Cherry 

 Creek, Dakota, in beds that both he and Meek referred either to the 

 Fort Union or Judith Biver series, but were unable to decide which. 

 While at the original localities these two groups seem to be sufficiently 

 distinct, subsequent discoveries (most of which are presented in this 

 report) of the fossils of each group associated in the same layers else- 

 where make it doubtful whether they will ever be recognized as dis- 

 tinct groups elsewhere than at the original localities. C. (L.) subelliptica 

 is described and figured in vol. ix of the United States Geological Sur- 

 vey ; and Mr. Meek there refers to this species as having been found in 

 the valley of Bijou Creek (where I also found it), as well as in the Upper 

 Missouri Biver region. It comes from bed No. 3 of the Crow Creek sec- 

 tion, where it is associated with several other species of that genus. 



No. 11. Corbicula (Leptesthes) pacta Meek. 



Several imperfect examples and fragments of a species, which is with- 

 out doubt identical with the one named above, were found in bed No. 3 

 of the Crow Creek section. The species, which is the type of the sub- 

 genus Leptesthes, was originally discovered in the upper part of the 

 Bitter Creek series, near Black Buttes Station, Wyoming. It has been 

 found there quite abundantly where it is quite variable in form, and 

 Where it also reaches a larger size than the average at the other localities 

 at which it lias been discovered. It is known at other localities west 

 of the Becky Mountains, and was also obtained by Dr. Hayden from 

 the same shaft with Nos. 1 and 13, two hundred miles east of Denver, 

 Colo. 



No. 12. Corbicula (Leptesthes) macropistha White. 



The type-specimens of this species came from No. 3 of the Crow Creek 

 section, but it was also obtained in the valley of Bijou Creek, and 

 at these two localities only. It is the smallest known species of this 

 subgenus, in which respect it contrasts strongly with the type-species 

 of Leptesthes, noticed in the last paragraph. It is described in the Bul- 

 letin of the Geological and Geographical Survey of the Territories, 

 vol. iv, p. 713. 



No. 13. Corbicula (Leptesthes) planumbona Meek. 



This species was obtained in considerable numbers from bed No. 3 of 

 the Crow Creek section, and also, but less plentifully, in the valley of 

 Bijou Creole. It was originally discovered "two hundred miles east of 

 Denver City, on the Kansas Pacific Railroad, Avhere they were found in 

 a shaft at a depth of 40 feet below the surface." By reference to 



