E-NDLICH.] VOLCANICS. 203 



basalt, surrounded ou all sides by granite. A sbort distance south- 

 ward, however, the volcanic area again began. Ascending Lake Fork 

 the two lower members of the trachytic series are met with. Opposite 

 station 11 (10,011 feet), iSIo. 1 has reached a good development. For 

 800 feet we find a series of grayish, pinkish, to red trachytes, weather- 

 ing in small fragments. Sanidite and hornblende are abundant in it ; 

 more particularly^ the latter. ISTear the base of station 11 erratic granitic 

 bowlders were observed ; not in great quantity, however. It is a coarse- 

 grained granite, of the first type that is described from the metamorphic 

 region. Subsequently discovered outcrops of this same granite, a short 

 distance from station 12, disclosed the origin of the bowlders. About 

 four miles south of station 11 is San Cristoval Lake, above which the 

 erratic metamorphic material is found in greater abundance than 

 farther below. The bowlders are larger, intermixed in the bed of the 

 creek with numerous small ones and pebbles. Although no distinct 

 evidences of glacial action were found either on the bottom of the nar- 

 row valley, or along the steep walls inclosing it, I am inclined to think 

 tbat such action must have produced the result observed. The valley 

 is a comparatively straight one up to the point where the granite comes 

 to the surface, and its form is that of a trough. IsTear the last large 

 bend, east of station 12, some of the granitic rocks, in positn, show a 

 very smooth surface. Inasmuch as the physical character of that 

 granite admits of weathering that would produce the same effect, I am, 

 therefore, not prepared to assert the existence of a glacier of hirge 

 extent at any former time, but it becomes a matter of great difficulty 

 to account for the existence of the erratic material at the localities 

 where it was observed unless that view be held. 



An interesting feature was observed at the north end of San Cristoval 

 Lake. From the east a rapid mountain-stream flows down into Lake 

 Fork, near the junction of which a large mass of yellow volcanic mate- 

 rial has been deposited. This material was not deposited by any volcanic 

 activity, however, bat was brought down from the eastern mountain- 

 ridge through the channel of the i)resenc creek. It seems improbable 

 that so large a mass should have been carried there by the compara- 

 tively small quantity of water, so that very likely snow-slides or even 

 glacial action may have contributed their share. By the means of this 

 body of soil and uudecomposed volcanic material having been lodged 

 immediately in the course of Lake Fork, that creek was dammed back, 

 and the present lake was formed. It seems probable that all, or at least 

 a very large percentage of it, must have been transported to the place 

 at once, otherwise the main creek would have been able, gradually, to 

 cut its way through, and the formation of the lake woitld thus have 

 been prevented. Judging from the "fresh" character of the surface, it 

 would seem as if this enormous land-slide had occurred but a compara- 

 tively short time ago. Small islands in the lake, only a few yards long, 

 with fir-trees growing upon them, speak for the same view. 



As mentioned above, a small amount of metamorphic granite crops 

 out near the last large turn of Lake Fork, overlaid by trachyte. 

 Station 12 was located on Is^o. 4, at an elevation of 13,967 feet, the last 

 prominent x^oint of a ridge running from north to south. This ridge is 

 remarkable for its beautiful detail form, and for the excellent develop- 

 ment of the "red stratum." We have again reached the region of high 

 mountains, and with it the higher trachytic strata. Ascending still far- 

 ther up the creek, we soon leave the lower members of the series alto- 

 gether and are in jSTo. 4. One of the most prominent points near the 

 headwaters of Lake Fork is Handle's peak, 13j997 feet high. Here the 



