white.] LAKAMIE FOSSILS OF DANFORTH HILLS. 211 



Hills Group, estimated to be about twelve hundred feet above its base. 

 In the overlying strata of the Laramie Group near by I found an abun- 

 dance of fragments of plants, but they were too imperfect for specific 

 identification. 



Crossing the axial flexure southeastwarclly, in the direction of White 

 River Indian Agency, I next examined the Laramie strata among the 

 Danforth Hills. As shown in my report for last year, the strata of the 

 Laramie Group have in this region an aggregate thickness of 3,500 feet; 

 and I am now inclined to regard its thickness as above rather than below 

 that estimate. This is somewhat remarkable when we remember, the 

 limited thickness of the group east of the Eocky Mountains, but the 

 thickness of the western Laramie strata is nowhere known to be greater 

 than that of those which are referred to the Laramie Group in Middle 

 Park. I obtained invertebrate fossils from two separate horizons of the 

 Laramie Group in the Danforth Hills, one of which is near the top, and 

 exactly equivalent with the fossiliferous horizon in the valley of the 

 Yampa, some twenty miles to the northward ; and the other is 200 to 

 400 feet above its base ; the two horizons being about 3,000 feet apart. 

 The upper horizon I found exposed in the gentle synclinal at the eastern 

 end of the Danforth Hills, about twelve miles due north from the White 

 River Indian Agency, and the lower one about four miles farther west- 

 ward. The only species found at the upper horizon in the Danforth 

 Hills is Ostrea glabra, the species which is so abundant at the same 

 horizon in Yampa Yalley and elsewhere ; but those of the lower horizon 

 are more numerous and very instructive, as the following list will show : 



LIST OF THE LARAMIE FOSSILS FOUNT) IN THE DANFORTH HILLS, 

 NORTHWESTERN COLORADO. 



1. Anomia micronema Meek. 



2. Volsella (Brachydontes) regularis White. 



3. Yolsella (Brachydontes) laticostata White. 



4. Nuculana inclara White. 



5. Corbicula cytheriformis Meek & Hayden. 



6. Corbicula % 



7. Corbicula (Leptestlies) fracta Meek. 



8. Corbula undifera Meek. 



9. Melania wyomingensis Meek. 



10. Odontobasis f formosa White. 



11. Cytherinaf 



12. Teliost fish-scales. 



NOTES ON THE LARAMIE FOSSILS OF DANFORTH HILLS. 



1. Anomia micronema Meek. 



The examples of this species are small, as they are in the valley of the 

 Yampa. They are preserved in the form of casts in the compact "reddish 

 shale that contains all the fossils of this locality, and show the numerous 

 radiating lines which characterize the species very distinctly. The dis- 

 tinctness and arrangement of these lines in some of the examples strongly 

 recall the appearance of Orthis or Hemipronites when preserved under 

 similar conditions in paleozoic rocks. The occurrence of this species 

 here, as well as at the other localities already mentioned, shows that its 

 vertical range is practically through the whole great thickness of ihe 

 Laramie Group. 



