EAST HUMBOLDT EA.NGB. 537 



in an obscure manner, so that their relation is not clearly made out ; their 

 position, however, is unconformable. 



There is reason to believe that the gneiss of Sacred Pass is constantly 

 descending in the series, so that the lowest members are re?.ched at the 

 southern end of the formation. 



The granite of White Cloud Peak bears a remarkable similarity to 

 some of the well-known Laurentian rock-masses of the Appalachians, while 

 the overlying schists and gneisses, with their limestones and heavy mica- 

 bearing quartzites, have a noticeably close resemblance to the eastern Huron- 

 ian. Thus isolated from a^ other large Archsean regions, and with only 

 the general petrographical outlines to decide from, no definite reference of 

 this interesting Archaean body can at present be made; but since all its 

 affinities lead toward the Huronian group, it is safest to refer it to that 

 division. 



The summits of the East Humboldt Range, from White Cloud Peak to 

 the northern end, all show abundant evidences of glaciation. Very consider- 

 able glaciers existed in the elevated group south of Fort Halleck. From the 

 region north of Lake Marian a fine view is obtained of the glacial canon 

 which forms the south branch of the South Fork of the Humboldt River. 

 The glacier here was 8 miles long, and its canon, presenting the character- 

 istic U-shaped bottom, shows a depth of 2,500 to 3,000 feet. The whole 

 range north of Fremont's Pass contains along its summit a series of deeply- 

 sculptured amphitheatres, with characteristic rounded bottoms, with roches 

 moutonnees, and carries along the lines of present drainage an abundance 

 of peculiar alpine glacial lakes. The rubbish of lateral moraines flanks the 

 canons. The upper 50 miles of the range presents a pretty continuous 

 field of glaciation. 



All the canons in the region of Clover Peak which descend to the west 

 side of the range are cut at least 1,800 feet deep, and in many instances 

 the glaciers flowed to the very edge of the plain. Upon the east side of 

 the extreme north edge of the range, in the region of Mount Bonpland, the 

 glaciers were short and steep, and have left abundant evidence of this in 

 massive piles of terminal moraines. The evidence also is very convincing 

 that since the Glacial Period erosion has be.en very insignificant. On Plate 



