56 OTTIDEBOOK OF THE WESTEEX UNITED STATES. 



Mount bhasta, with the rugged cliits of Sheep liock on tho right. 

 These cliffs arc composed of dark lavas and tuffs, which dip cast. 



Mount Shasta continues in sight for many miles. Tho most im- 

 pressive view is obtained from the station called Mount Shasta, Tho 

 mountain has two simimits. The higher one, on the left (14,380 

 feet), is that of Mount Shasta proper; the lower one (12,433 feet) is 

 Shastina. Whitney Glacier lies hetween the two peaks and is over 

 2 miles long. A prominent gray pile of bowlders and gravel, clearly 

 in view at the lower end of the glacier, is its terminal moraine. 

 Mount Shasta above a level of 4,000 feet is composed of lava, chiefly 

 a kind containing less silica and generally lighter in color than basalt, 

 known as andesite. There are a few basalt cones about the base of 



tho mountain. 



known 



as the Haystacks, composed of sedimentary and intrusive rocks like 

 those of tho Klamath ilountains and formii 

 tho sea of lava. 



About 5 miles beyond the Haystacks, on tho riglit, is a steep httlo 

 valley formed by a caved-in lava tunnel. Wlien the supply of lava 

 is cut off at the close of an eruption the molten interior of a flow 

 continues to move down hill under its hardened crust, leavmg tuimel- 

 like caves which may be a mile or more long. 



Beyond this valley is a gravel deposit made by Wliitney Creek, 

 which is fed by Whitney Glacier. The creek has cut a deep canyon 

 for several miles below the glacier, but before it reaches the point 

 where the railroad crosses it the stream becomes overloaded with 

 gravel and has to drop part of its load. In summer the creek dis- 



appears in the porous gravel deposit. 



down the sides of Mount Shasta 

 id swings to Weed. 



MATS 



Tins 



narrows 



hills of Cretaceous rocks are close to the railroad. The gravels formerly 



worked in the placer mines seen along here on the 

 right (southwest) are for the most part of Quaternary 

 age. Some gold, however, has been obtained from 

 a Cretaceous conglomerate whose pebbles were derived 

 directly from the still older roclvs on which the con- 

 glomerate rests. The best known of these placers are those of the 

 Forty-nine group, near Phoenix, wliich have yielded not only much 



^1 ^B ^^H ^^^V 



Phoenix. 



Elevation 1,566 fc 

 Topuiation 250. 



Seattle 519 miles. 



The 



^v.... ^^^ ^^^ u. number 



^^cks on which the Cretaceous condomcrate 



8C3.* 



'iD 



miles. ^^^.*^ ^^^ possibly Paleozoic. Farther south, in the 



neighborhood of Ashland, these rocks are succeeded 



CTanular 



■o to 



srranite 



