OKES OF THE CAMIUIIAN. -J'X) 



as those so successt'ully worked on l\ul)y Hill, aivt'oimd tlinmulnuit ;i wide 

 vertical range of sedimentary beds. No ore deposits are known below the 

 contact between the Pi-osjject Mountain (juartzite and the overlying- lime- 

 stones upon l\uhv I nil. As will l)c shown later these limestones on Ruby 

 Hill carry deposits of ore throughout their entire thickness from the (piartz- 

 ite to the overlying Secret Canyon shale. 



Along the slopes of Prospect Mountain from .Mineral Hill southward 

 to Surprise Peak, the crushed and brecciated limestones have undergone 

 considerable local disturbance and are honeycombed throughout Ijvfissures, 

 seams, and irregular crevices of various width and length. Many of these 

 openings lie parallel with the stratification; others cut across the beds, occur- 

 ring in the limestone anywhere between the quartzite and shale without any 

 recognized order. Oxidized ore bodies occupy these openings, many of 

 them being connected by narrow chainiels and seams more or less tilled 

 with mineral matter. The Williamsburg mine on the west side is a good 

 example of the oi-e fouml de])osited in characteristic chambers, while on the 

 east side at the extreme southern end of the ridge the Geddes and Bertrand 

 mine appears to be a well defined north and south fissure carrying much 

 rich ore. Among others of the larger bodies of ore may be mentioned those 

 of the Silver Connor and Banner niines, the latter a good example of a fissure 

 which occurs on the summit of the i-idge. In but few of these ore bodies, 

 at least on the surface, have any rhyolites been recognized. A marked 

 instance, how'ever, may be seen in the case of the Greddes and Bertrand 

 mine, where a powerful east and west dike cuts the limestone and overlying 

 shale in close proximity to the north and south ore channel. 



Nowhere along the grand exposures of Secret Canyon shales have the 

 ores penetrated to the surface, the jiliable, argillaceous clays Hexing and 

 folding instead of fissuring-, and e^•erywhere serving as an imper\-ious 

 barrier to the ascending currents. Fine examples of dike cutting are 

 shown near the Geddes and Bertrand Mine and again on the summit of the 

 watershed between New York Can^'on and Secret Canyon shales, but at 

 the latter locality, so far as known, whollv unaccompanied by important 

 mineral matter. 



The beds of the Hamburg limestone ar(^ similar in their structural 



