468 GEOLOGICAL SUEVEY OF THE TEREITOEIES. 



mas, already described. On the west side, these bluffs are rather more 

 precipitous than on the east, and come down closer to the stream-bed. 

 These consist usually of a series of bluffs one above the other, receding 

 from the view. Over the last tier, which is from 1,000 to 2,000 feet-above 

 the stream, numerous small streams of water pour, and passing over 

 the succeeding bluffs in falls and cascades present a beautiful spectacle. 

 In the early spring, when the snow is melting and they are swollen to 

 considerable streams, the sight must be magnificent. A number of 

 mines are located high up the slopes wherever they are not too steep to 

 be ascended. Here and there a little low but is visible on the east 

 slope. Near the head of the gulch the trail is very muddy and badly 

 cut up by travel. The upper part of the caiion ends abruptly with 

 steep, high bluffs on all sides, except the narrow strip up which the 

 trail winds to the pass. Several lodes are located at the head of the 

 gulch. The amphitheatrical form of the head of the caiion with the 

 great bluffs are very characteristic of volcanic formations, and all over 

 the San Juan region they are the rule rather than the exception. Nev- 

 ertheless, the sudden termination here of the great Cunningham Gulch 

 is exceedingly interesting. The stream falling over these bluffs serves 

 to heighten the effect. 



The trail now leaves the creek and ascends the east slope. It is very 

 steep and always muddy and slippery. The grade may be appreciated 

 by calling to mind the fact that from the bed of the stream to the pass 

 the rise is about 1,500 feet in one and a half miles horizontal. 



The incessant travel over this trail by the miners, with their horses, 

 mules, and burros, keeps it in a bad condition. Although it can scarcely 

 be said to be dangerous, still its slipperiness adds much to the labor of 

 the already overwrought beasts of the miners. The really bad part of the 

 trail is only a small part of the whole distance. On the summit the 

 ground is gently rolliug, and the trail passes between low hills which 

 form the principal part of the country in the immediate vicinity. The 

 elevation of the pass above the sea, as determined by a single reading 

 of the mercurial barometer, is 12,090 feet. 



We made station 17 on a table a short distance southwest of the pass. 

 From this vicinity a good view of a number of the most rugged of the 

 quartzite peaks may be had. Those that appear range in height from. 

 13,600 to 13,800 feet. After camjiiug overnight on the head of the Eio 

 Grande, the next day we made station 18 on a peak between Pole and 

 Lost Trail Creeks, whose elevation is 13,650 feet. From this peak we 

 had a good view of the country south of Lake Fork. In this vicinity 

 are scattered a number of pretty high peaks, but they are generally iso- 

 lated from each other, and have none of the massiveness of the mount- 

 ains about the head of Lake Fork and the Animas. In ruggedness 

 they cannot compare with many that will be described further on. To 

 the east the slopes begin to be more gentle, and at a distance of a few 

 miles ajipears a pretty extensive i)lateau surrounded by high bluffs. 

 The next day, in passing down the Rio Grande, we noticed a very pecu- 

 liar formation consisting of a very bright-green- colored rock weathered 

 into little needles and spires. It is situated against the south side of 

 station 18. After camping near the junction of Lost Trail Creek with 

 the Eio Grande, we made two stations on the high plateau, just to the 

 east of the camp. The climb was very difficult on account of the great 

 masses of fallen timber we encountered and the bluffs that came in our 

 way. Once on the top of the plateau, the riding was very easy. It was 

 covered with loose rock, (trachyte,; but not so much so as to seriously 

 impede our course. There being no prominent point, we were compelled 



