228 GEOLOGICAL SUEVEY OF THE TERETTOEIES. 



This will be more clearly sliown as we progress. First, we will speak of 

 Buckskin Gulch. Buckskin Creek, like all the streams heading in the 

 Park range, has cut profoundly into the rocks, giving us an excellent 

 opportunity to study the geological structure. As I have said before, 

 the creek rises on the southeast side of Triaqua, or Buckskin Mountain, 

 and flows toward the southeast, around the west side of Mount Bross, 

 and empties into the South Platte. Passing through the deserted town, 

 Avbich was once a mining center, we soon find ourselves in the canon. 

 On the top of the wall-like bluff on either side, capping it, are quartzites 

 and limestones dipping a little south of east, at an angle of about 10<^ 

 to 15°. 



Approaching more closely, we see that the quartzites resting on the 

 granite are faulted. The appearance of the bluff-like wall is shown in 

 Fg. . This is on the south side of the carton. The following section 

 in ascending order is made on the line a/, in Fig. 3, Plate VII : 



Section No. 16. 



a. 1. Granites, coarse and rose-colored. They extend to the bed of 



the creek covered with debris. 

 1). 2. Very hard white quartzite, 20 to 30 feet. 



3. Greenish volcanic rock, growing wider as we go toward the 

 west and thinning out to the eastward, 15 feet. 



c. 4. White quartzite, 10 feet. 



5. Greenish volcanic rock, terminating in a wedge-like point. It 

 has split ISo. 4 from the bed above, (So. 6,) 12 feet. 

 i 6. White quartzite, really a part of No. 4, 6 feet. 



d. } 7. Brownish snuff-colored quartzite, 2 feet. 



( 8. Light-colored quartzite, with dark bands,14 feet. 



9. Greenish volcanic rock, terminating in a wedge-like point, the 



point this time being to the westward, while before, in No. 5, 



it was toward the east, 12 feet. 

 ^ 10. Dark-colored quartzites, 6 feet. 



11. Light-colored quartzites, 8 feet. 



12. Banded quartzite, in layers about a foot thick each, gray and 



e. ■{ rust-colored, 12 feet. 



j 13. Light pinkish quartzite, 4 feet. 



I 14. Dark reddish quartzite, 15 feet. 



[ 15. Banded quartzites, about 100 feet. 

 These beds correspond to the quartzites on the side of Mount Lincoln, 

 and are undoubtedly only their southern prolongation. As we go up 

 the creek we find that there is a large fault, and that we again come to 

 these beds dippiug in the same direction. The line of this fault if pro- 

 longed would pass to the west of Mount Lincoln near Triaqua Mountain. 

 It probably extends into Mr. Marvine's district. It also continues to the 

 southward, where we shall refer to it again ; the down-throw is to the 

 west. In Mosquito Gulch, the next one south of Buckskin, the same 

 beds occur with the same great fault, and with smaller local faults in the 

 quartzites. Mr. Taggart made the following section on the south side 

 ot the creek. It is made to the right of the fault (AB, CD, EF,) shown 

 in Figs. 1, 2, and 3, Plate VIII. 



Section No. 17. 



1. Eeddish volcanic rock. 



2. Dark quartzite, (reddish,) 3 feet. 



3. Light quartzite, dipping 20° toward east, 8 feet. 



