162 GEOLOGICAL SURVEY OF THE TERRITORIES. 



thoiigb these pine-covered areas may, in part, be granite bosses rising 

 above tlie surrounding beds. All the lower terraces and bottoms are 

 free from timber. Between the terraced filling may still exist remnants 

 of the sedimentary rocks which probably originally filled the basin. 

 The only sedimentary rocks examined, however, were along its northern 

 border. East of where the Frazier Elver enters its caGon, and along 

 the stream, followed by the Boulder Pass road, there are a few exposures 

 which the stream has cut out of the adjacent terraces. One, about a 

 mile east of the canon moutb, is between 60 and 80 feet high, and is 

 composed of light-drab sandy beds, weathering white, from four to 

 eighteen inches thick, mostly somewhat indurated ; considerable clayey 

 sand, and some lenticular bodies of gravel. Pebbles in the latter are of 

 gneissic and granitic rocks, reaching two inches in diameter. Some of 

 the sand is quite fine, with scattered pebbles, and some layers of grains 

 of chalcedonic or agate-like quartz. 



The dip of all is from 5° to 10^ to southwest. This branch of the 

 Frazier Eiver lies mostly in these beds, but at a few points near the 

 granites on the north it cuts through little southward-projecting points 

 of the latter which are surrounded by the sediments. The lower river 

 terraces have much sage brush sprinkled over them. In the northwest- 

 ern corner of the basin, from two and a half to three miles west of the 

 canon entrance, the low hill-slopes near the road show some dull, dark, 

 somber, brown-colored sandstones of coarse texture, which dip 8° or ] 0° 

 to the southwest. They are at first composed mostly of quartz and 

 fieldspar, with some mica, debris from the surrounding metamori^hic 

 rocks 5 but farther on small pieces of red and whitish sandstone occur, 

 growing larger as one advances, till frequently one-half to one inch in 

 diameter, and usually brecciated rather than rounded. They are i)rob- 

 ably derived from the hard sandstones of Cretaceous No. 1, which occur 

 farther on, and show that these beds of the Frazier do not belong to 

 the older sedimentary series of the park, while their general characters 

 indicate that they are very recent, probably the same as the usual lake 

 beds, and derived from tbe rocks immediately around. The fact that 

 these recent beds incline slightly is interesting. 



About three miles from the caiion. the road passes from these beds to 

 the smoothed granite region of the low divide, and passes over into 

 another portion of the grand drainage, to which we will now turn. 



THE REGION IN THE VICINITY OF THE HOT SPRINGS. 



The region that will next attract our attention is shown in the accom- 

 panying map, (Fig. 10,) the relations of which to the park in general 

 may be seen by glancing at the general map, (Fig. 8.) A section (A. B) 

 across the same is given on Plate III, section 1, which shows, also, the 

 character of the country lying north of the section. 



It is but a mile or two after leaving the sandstones of the Frazier 

 basin, across the low granite divide just spoken of, to where the road 

 enters the lower side of the inap. It soon divides the right-hand trail 

 going to Grand Lake, the left-hand road continuing on to the Hot 

 Springs. Following the latter a little past the branching, some of the 

 recent sandstones, similar to those just left, appear upon the granites, 

 foUow^ed by a small ridge of a hard white sandstone, dipping at an 

 angle of 55° to the northwest. The exposure is small, and the outcrop 

 was not observed extending toward the hills to the southwest. Follow- 

 ing along the exposure over the ridge to the northeast, and in the valley 



