S AH- WAVE MOUNTAINS. 803 



phosed, like those of the entire region, have been examined microscopically 

 by Professor Zirkel, who pointed out their resemblance to the Silurian and 

 Devonian crystalline slates of Germany; but, while the similarity is quite 

 marked, it should be borne in mind that it is only in the products of meta- 

 morphism, and, it would seem, might easily be found in strata as altered 

 as the Mesozoic beds of Western Nevada. Quartz and extremely minute 

 laminse of nearly colorless mica are the only minerals that could be recog- 

 nized with a high power under the microscope. 



Sah-wave Mountains. — The Sah-wave Mountains measure 20 miles in 

 length by about 6 miles in width, and are but a continuation southward of 

 the Pah-supp group, terminating near the line of the 40th parallel. They 

 present their steepest slopes toward the east, the highest point rising over 

 3,000 feet above Sage Valley, and fall away in the direction of the Truckee 

 Eange, with which they are connected by a narrow depression. So far as 

 examined, the granite resembles that of the Pah-supp Mountains, and is 

 evidently of the same type. A specimen from the summit of the highest 

 peak is of a light-gray color, owing to the small amount of hornblende and 

 biotite present. The quartz has a slight grayish tinge. Under the micro- 

 scope, in thin sections, the orthoclase crystals reveal the presence of included 

 fragments of stiiated plagioclase. 



On the flanks of the highest peak, the gray slates are exposed in the 

 same manner as seen to the north, dipping eastward, upon which, resting 

 unconformably, are the upturned Truckee Miocene beds, made up of light- 

 colored, variegated strata. Two or three miles to the southward, the Miocene 

 is seen for a short distance resting directly upon the granite, beyond which 

 it is in turn concealed by the Quaternary. 



Truckee Range. — This range extends in a north and. south line for 

 72 miles, and consists, for the greater part of the distance, of a single narrow 

 ridge barely more than 5 miles from base to base, but widening considera- 

 bly at the southern end, where it is made up of broad fields of Tertiary 

 eruptive rocks. Its trend is almost due north and south, the meridian of 

 119° 15' cutting the crest of the ridge for its entire length, the culminating 

 peaks being sometimes on one side of the line and sometimes on the other. 

 Tutib Peak, at the southern end, Nache's Peak opposite Winnemucca Lake, 



