310 



ANNUAL REPORT SMITHSONIAN INSTITUTION, 193 5 



interbedded with angular fragments of andesitic lava. In places the 

 pumice rests directly upon the well-striated surface. 



Near North Entrance Ranger Station (5). — Beneath pumice and 

 what appears to be a much-fractured lava formation is an old weath- 

 ered surface which exhibits well-developed glacial grooves (pi. 4, 

 fig. 2) . The poor preservation of the surface and its buried location 

 suggest that the markings are older than those found just north of 

 the Devils Backbone. If talus material did not cover so much of the 

 inner slope at this point, it would probably be possible to relate this 



STR/AE 



N.es^'E 



PUMICE AND 



FRAGMENTAL 



MATERIAL 



STRIAE 

 N.lfE. 



TILL 



STRIAE 



10 FEE T 



Figure 8. — Three stages of glaciation at Glacier Point. Locality 2. 



grooving to the earlier of the glacial stages recognized at Discovery 

 Point. 



Llao Rock (6). — From a point on the rim just east of the North 

 Entrance Ranger Station it is possible to view the steep front of 

 Llao Rock. If one is equipped with a pair of good boots, it is pos- 

 sible to crawl along at the base of the steepest portion and reach 

 a position marked A in plate 5, figure 1. Here, buried beneath the 

 lava of Llao Rock, is a heavy boulder till containing numerous well- 

 striated stones ranging from a few inches to a foot in diameter. 

 The material is characteristically glacial in appearance. A few hun- 

 dred feet farther down the slope, and several hundred yards to the 



