24 Stone — Granitic Breccias of the Cripple Creek Region. 



the simple magnifier it appears devoid of glass and substan- 

 tially like the ordinary scoriaceous and somewhat cellular pho- 

 nolite found at the top of many of the dikes in this district. 

 The smoothed blocks that form the outcrop of this dike form 

 low ridges from 200 to 500 feet wide. If there had been a 

 large amount of erosion since their deposition, they would not 

 as now form compact heaps but would have become widely 

 scattered down the hillsides. 



3. The Alhambra. Elevation 9730 feet. 



This mining claim is situated low down on the southwestern 

 spur of Squaw Mountain. 



A granite ridge is here strewn with bowlders of a firm sand 

 rock, composed almost wholly of crushed granite. Much of it 

 is somewhat porous by the removal of the feldspar and mica 

 grains by vein waters. In some places the rock is practically 

 quartzite by the replacement of the mica and feldspar with 

 silica. It contains a small proportion of crushed phonolite. 

 The more siliceous and iron rusty parts run high in gold, and 

 some 150 tons of bowlders of this class have been picked up 

 on the surface and were shipped as good pay ore. 



Several shafts, pits, and trenches, now mostly inaccessible, 

 show that a phonolite dike here rises through the granite, but 

 none of the solid dike reaches the surface. Specimens sup- 

 posed to come from a depth of 80 feet show that at that depth 

 the phonolite is frozen fast to the granite. Nearer the surface 

 is a body of uncemented phonolite gravel, proving that this 

 portion of the dike was pushed forward and broken up after 

 solidification. Nearer still to the surface is a body of mixed 

 granitic and phonolite gravel, somewhat cemented. At the 

 surface and scattered over the adjacent granite are the bowlders 

 of sand rock already described. These bowlders have smoothed 

 surfaces, proving that after the sand had become cemented 

 into a solid rock, the rock was fractured- by the upward move- 

 ment of the dike and the blocks then received a secondary 

 grinding. They were piled in a ridge along the line of the 

 dike and in the course of time have become scattered over an 

 area about 300 feet wide. This is proof of a limited erosion 

 since the dike period. This fact together with the finding of 

 gold in the sandstone unite to prove the eruption compara- 

 tively recent. 



Squaw Mountain rises steeply several hundred feet above 

 the Alhambra, which is thus proved to lie far below any 

 ancient floor of the sea. The sand-rock cannot be a remnant 

 of a marine bed. If it be the remains of a lake bed, where is 

 the rest of the bed ? There is no other rock like this within 

 half a mile of the Alhambra, though there are several similar 

 deposits of sand-rock in the town of Victor and vicinity, but 



