st.johx.] SECTION LARAMIE GROUP. 353 



terminates. In this steep slope the following- ledges are imperfectly 

 exposed : 



7. Dark gray calcareous gritty bed, sometimes conglomeritic or brec- 

 ciated, containing numerous poorly preserved Lamilhbranchs, Gastero- 

 pods, and vertebrate remains, probably fishes. The fossils are impacted 

 in the tough matrix, from which they are obtained in so mutilated con- 

 dition as to render their identification doubtful. Dr. White, however, 

 refers one of the most prevalent forms to Unio, at the same time noting 

 a resemblance it bears to forms occurring in the Laramie beds in the 

 region to the south. The Gasteropods are indeterminable, while in 

 regard to the vertebrate remains, which were submitted to Professor 

 Cope, their affinities remain as yet undetermined with the exception of 

 some small-sized gar scales which, although not specifically determin- 

 able, are probably of Tertiary age. 



8. Underlying the last-mentioned stratum occurs a thickness of sev- 

 eral hundred feet made up of red and drab gritty shales, including soft 

 gray sandstone layers, which descend into the saddle north of Station 



XVI, where they rest upon — 



9. Fragmentary drab limestone, forming a low debris-strewn ridge at 

 the foot of the descent. This outcrop may be traced at intervals more 

 or less interrupted in a southeasterly direction, reappearing in the low 

 ridge between the forks of John Gray's Creek northwest of Station 



XVII, where its outcrop gives a banded appearance in the grassy slopes. 

 It contains numerous individuals of a small undetermined Gasteropod. 



10. Ascending the long slope to the north, the latter limestone is im- 

 mediately followed hi descending order by gray, cross-bedded sand- 

 stone, interbedded with chocolate-red shales and indurated ferruginous 

 layers. These beds form a heavy deposit, showing local disturbance, 

 but with a normal dip S. 45° W. at an angle of about 20°. 



11. Higher in the slope the position of another limestone bed is marked 

 by the drab, fragmentary debris which strews the surface. Besides a 

 fragment of bone, there were also seen other obscure fossils. The rock 

 is less brittle and lighter colored than bed 9. 



12. Dirty and sometimes reddish-buff, very hard, brittle, spar-seamed 

 sandstone. The rock shows slickenside surfaces, is almost the hard- 

 ness of cpiartzite, and contains vegetable impressions like sections of 

 limbs. Its debris covers the surface extending up into the summit,, 

 which is capped by a heavy ledge of — 



13. Grayish-blue trachytic rock, having a distinct bedded structure,, 

 in firm, uneven layers 2 to 12 inches or more in thickness. The rock 

 presents a low wall in the crest of the hill facing southwestward, in. 

 which the exposed edges of the layers reach a thickness of 5 to 15 feet,. 

 dipping 40°, X. 50° E. 



Such as they were, the few obscure vegetable remains found in con- 

 nection with the sandstones of the foregoing section were submitted to: 

 Professor Lesquereux for examination, who kindly informs me that, 

 though too indistinct for minute determination, they are undistinguish- 

 able from similar vegetable relics prevalent in perfectly authenticated 

 Laramie beds at numerous localities in the Northwest. This, together 

 with Dr. White's determination of the probable affinities of the inverte- 

 brate fossils before alluded to, as well as the probable relations of the 

 vertebrate remains communicated by Professor Cope, afford ground for 

 referring all these deposits to the age of the Laramie Group. As we 

 shall have become more familiar with the fauna and flora of the rocks 

 of these distant regions, the doubts of to-day may appear almost without 

 foundation and vanish. But these results are the outgrowth of time, 

 23 GS 



