THE SCHISTS. 51 



A distinct discordance of dip between rocks representing the characters 

 of these two groups was seen by Mr. Jenney in the west canon of Castle 

 Creek, but in the absence of corroborative observations, the fact of the 

 unconformity of the two series cannot be insisted upon. 



The western series consists of quartzose schist and ganietiferous, quartz- 

 ose, and ferruginous, mica schists, together with some gneiss, chloritic and tal- 

 cose (or hydrous mica) schists, hornblendic schist, and quartzite. The whole 

 series is coarse in texture and highly crystalline, and it contains many 

 seams or veins of quartz traversing the schists conformably with the strati- 

 fication and having usually a swelling or lenticular structure. These veins 

 are interlaminated veins and are not often of any great width; they contain 

 finely disseminated gold, and have probably afforded by their disintegration 

 the larger portion of the gold found in the valleys and gulches. The granite 

 masses are found wholly within the area of the schistose rocks. The east- 

 ern series is composed of metamorphic rocks distinguished from the western 

 mainly by their exceedingly fine and compact texture, though, as shown by 

 Mr. Caswell, their ultimate mineral composition is quite similar. The rocks 

 are mainly micaceous clay slate, clay slate, silicious slate, and quartzite. 

 The last forms persistent strata from 50 to 200 and sometimes 500 feet in 

 thickness, which may often be traced for long distances with little variation. 

 The quartzite frequently contains seams or veins of interlaminated or 

 ribbon quartz, and with them are associated large deposits of hematite or 

 specular iron ore, also interlaminated with quartz. Frequently the quartz 

 seams are highly ferruginous and in places they have been found to con- 

 tain undecomposed pyrites. Unquestionably they are often auriferous. 



Micaceous schist is the prevailing and most characteristic rock of the 

 western series, but its variation in character is very considerable. More 

 commonly it is a gray, tolerably fine, highly crystalline, uniform, micaceous, 

 silicious schist, which, from its large proportion of mica, weathers readily 

 and uniformly. Very frequently, especially in the western part of the area, 

 it is so highly charged with garnets that it acquires a dark reddish color. 

 The garnets are well crystallized but of small size, rarely exceeding a 

 quarter of an inch in diameter. In the weathering down of the garnet- 



