Geol.— Vol. I.] TURNER— ORIGIN OF Y OS E MITE VALLEY. 303 



The western moraines are in part terminal,' and such have 

 caused the formation of meadows and the silting up of the 

 valley. Pebbles are common and nearly all contain boul- 

 ders of the coarse porphyritic granite, with feldspars three 

 inches or more in length, which is found in place about 

 Lake Tenaya. 



There is no evident terminal moraine at the extreme west- 

 ern end of the valley, w<here it suddenly narrows into a 

 canyon. The moraines observed are of suflicient size, 

 however, to have effected the silting up of the valley; for 

 they rise some feet above the valley floor about them. More- 

 over, it is quite certain that if we should clear the valley of 

 its alluvial deposits and talus, thus exposing the moraines 

 in their original dimensions, we would find that those now 

 visible were formerly much larger, and that some exist 

 which are now buried from view. There is also what 

 appears to be a small moraine by the Wawona road, at an 

 altitude of 5,000 feet, about northwest of Inspiration Point. ^ 



Glacial markings were noted at the following points, 

 beginning at the upper end of the valley. At the top of 

 Nevada Falls, there is glacial polish; also between the 

 Nevada and Vernal falls. Just northwest of Mirror Lake, 

 about forty feet above the water-level, is a patch of glacial 

 polish about thirteen feet in length, showing also strise well 

 preserved. About 1,200 feet above the lake, on the south- 

 east slope of North Dome, the granite shows groovings in a 

 marked manner. Distinct groovings may be seen on the 

 valley walls at the following points when the light is favor- 

 able, and especially after a rain, when the rocks are wet: 

 namely, on the north wall 300 (?) feet above the valley 

 floor, and about 1,000 feet east of Indian Creek; on the 

 north wall 800 (?) feet above the valley floor, and about 



1 Professor Chamberlin, Third Aunual Rept., U. S. Geol. Surv., p. 302, suggests that it 

 is importatit to distinguish between moraines which mark an important advance of the 

 ice and those which merely indicate a temporary halt or insignificant advance; and he 

 proposes that we should use "terminal moraine" for those of the first class, and 

 "peripheral moraine " for those of the second class. The term is, however, used here in 

 its ordinary sense. 



2 The point here referred to is the one so called on the topographic map of the Geolog- 

 ical Survey, and not the one by the Wawona road. 



