Vol. 6] Bcid: The Geomorphogeny of the Sierra Nevada. 95 



and of fine grain. No limestone as such has been recognized in 

 the area examined. On the east slopes of Mt. Davidson, in the 

 underground workings of the mines at the north end of the Corn- 

 stock lode, 5 limestone was cut. This probably belongs with the 

 metamorphie rocks to the west. At Lakeview Hill and north of 

 Carson there are evidences of limestone in the great development 

 of lime-bearing contact minerals. The planes of schistosity are 

 nearly, if not cpiite, coincident with the bedding. The dip and 

 strike are in all directions and angles, due to the plutonic in- 

 trusive. On Lakeview Hill the schists lie approximately parallel 

 to their contact with the granite, striking about N 32° E and 

 dipping SE 68°. Where the schists are not greatly disturbed 

 and sunken into the plutonic rock, the schistosity is usually 

 roughly parallel to the contact, as at Lakeview Hill, In the very 

 small area west of Lakeview the schists stand about vertical, 

 striking roughly north and south. AY est of Carson, from Kings 

 Canon up, the lowest rocks are schists, standing vertical and 

 striking parallel to the canon; the higher rocks are andesitic 

 flows and tuffs striking northeast and southwest, and dipping 

 gently to the northwest. The age of the metamorphie rocks is 

 referred to the Jura-trias, in keeping with Lindgren's conclusions 

 in the Truckee quadrangle. That area centering about Ward's 

 Peak, west of Tahoe City, is composed of rocks apparently identi- 

 cal with those of the Nevada region. Lindgren has presumably 

 classed the Ward's Peak area with the Sailor Canon formation, of 

 unquestionable Jura-trias age. Prom the similar character, 

 areal distribution, and relationship to the granite, it appears 

 probable that the various isolated patches of schists are to be 

 correlated with one another and with the metamorphie rocks west 

 and southwest of Lake Tahoe, and originally forming the com- 

 plete roof of the great batholith of the range. 



The Irruptive Contact. — The irruptive contact of the granite 

 and metamorphie rocks presents another important and interest- 

 ing problem. The best exposure of this contact is in the rail- 

 road cut, on Lakeview Hill. A second good, though small', ex- 

 posure, is in the hills north of Carson. The other exposures are 

 not so promising for further study. At Lakeview Hill the con- 



■< Becker, U. S. G. S. Mod., III. 



