PEALE.] 



GEOLOGY SECTION NO. 17. 229 



4. Reddish volcaoic rock, 12 feet. 



5. Light quartzite banded with dark, 5 feet. 



6. Gray quartzite. 



^ e. 8. Greeuish volcanic rock, 10 feet. 

 ^ ^ I 9. Light quartzite 5 unable to get thickness. 



, |_^" ^' J 10. Micaceous sandstone, 4 feet. 



I'iate Vlii. ^^^ White quartzite, 8 feet. 



[ d. 12. Eeddish volcanic rock, 15 feet. 

 _. ^ (c. 13. White quartzite opposite volcanic rock. 

 -^^^' -'-?,^ ) b. 14. Greenish volcanic rock, 8 feet. 

 I'late Vill. ^ ^^ ^^ Qj.^y quartzite, 6 feet. 



16. Micaceous sandstone, 4 feet. 



17. Grav quartzite, with bands of brown sandstone, 



26 feet. 



18. Pink sandstone, with bands of pink shales 2 to 6 



inches thick, 3 feet. 



19. Gray quartzitic sandstone, 40 feet. 



20. Compact gray limestone, 15 feet. 



From Mr. Taggart's notes I take the following : " Below bed No. 2 

 there is gneiss on the same jjlane with a gray quartzite,/, in Fig. 3, Plate 

 YIII. From diagram ]Sro. 2 to 3 the line of the fault is continuous. 

 The fault is filled" with volcanic rock, which can be very readily traced. 

 The diagrams had to be made in sections. The line is not uniform. 

 The volcanic rock at the bottom of diagram No. 2 is probably continu- 

 ous with that at the top of No. 2, but there was so much debris that I 

 was not able to ascertain definitely if it was or not." 



The quartzites in Mosquito (el ulch dip more nearly to the east than they 

 do in Buckskin. The angle is about 15"^. Going up creek we find the 

 same fault we saw in Buckskin,, and after passing the gneiss we find a 

 small patch of quartzites, still dipping east but at a less angle. The 

 gneiss has seams of volcanic rock. Then we have another fault, the 

 line a b in Fig. 1, Plate VII, which shows the appearance on the 

 south side of Mosquito Creek. A short distance farther up, between 

 the forks of the creek, is an isolated hill. (Fig. 2, Plate VII, shows 

 this hill looking north.) The eastern end is gneiss, then follows vol- 

 canic rock, and at the western end the same beds of quartzite outcrop 

 that we saw at the mouth of the caiion. When we cross to the Arkan-^ 

 sas side of the range we find them again, while between is a layer of 

 very massive volcanic, rock. In addition to the quartzites on the Ar- 

 kansas side are very dark, almost black, limestones, which probably 

 belong to the Quebec group. These rocks are all highly metamor- 

 phosed. The divide itself is composed of a volcanic rock with Silurian 

 strata above. Between the divide, which has an elevation over 12,()()(> 

 feet, and the hills to which we have just referred, and which are shown 

 in the illustrations, there is a low pass, the direction of which is north 

 and south. On the branches of Sacramento Creek — the next south of 

 Mosquito — the same beds are lifted up on the granites. 1 did not go 

 up the creek, but doubtless the same faults exist that are seen on tlie 

 other streams. It was on Horseshoe or Four-Mile Creek that we wore 

 able to make the most complete sections. The following section was 

 made from the mouth of the caiion of Four-Mile Creek westward to 

 Horseshoe Mountain. It is in descending order : 



Section iVo. 18. 



a. 1. Brown metamorphosed sandstone, 3 feet. 



