WEST HUMBOLDT EANGE. 719 



north 30° east, with a dip declining" toward the plain. In the region of the 

 flexures around the northern end of the schist formation, there are seen 

 numerous radiating- and vertical fissures, besides a second series of faults 

 developed in a northeast plane, or approximately parallel with the line of 

 strike. There does not seem, however, to be any considerable amount of 

 displacement in connection with these fissures. In the limestones, in the 

 region of Wright's Canon and the large calion to the north, are irregular veins 

 of feldspar, with occasional but rare masses of milky-white vein- quartz. 



Diligent search was made in these flexed and altered limestones for 

 organic remains, but the impressions found were too much obliterated for 

 determination, with a single exception, that of an 



Ammonites Blakei, 



identical with those found in Star and Coyote Canons on the east side of 

 the range. All observations tend to show that the part played by this 

 Archaean body has been, during the period of upheaval of the range, to 

 push its way upward through the sedimentary strata, and bend them in a 

 bold semicircular curve around the north and west side, lifting them from 

 an average 30^ dip by waving curves up to the vertical position. 



The westerly-dipping quartzites and porphyroids of the Koipato series, 

 striking diagonally across the range, occupy the head and valley of Indian 

 Canon; thence northward they form the main ridge on both sides of Cotton- 

 wood Canon, and the narrower portions of Buena Vista Canon. Crossing 

 Coyote and Bloody Canons, they appear in the low hills near the entrance 

 to Star Canon, and die out in the plains a short distance northward. The 

 thickness of these beds has been roughly estimated at 6,000 feet. 



Star Canon opens up from the plain through beds of dark slaty quartz- 

 ite, having an irregular and imperfect cleavage. In certain layers, it is 

 somewhat calcareous, and, in the lower members, shows much argillaceous 

 material. This is the zone which prolonged southward continually under- 

 lies the lowest Star Peak limestone, gradually becoming thinner and more 

 and more altered until it passes into the highly metamorphosed and true 

 porphyroids. The siliceous zone directly under the limestone in the region 

 of Coyote Canon is, near the top, a fine-grained red and yellow marl, and 

 passes downward through arenaceous and argillaceous beds into compact, 



