THE COMSTOCK LODE. 69 



included within the lode. Like the propylite horses, they are subdivided by 

 a net-work of unimportant fissures, and rendered somewhat plastic by the 

 ordinary solfataric action; but they have not arrived at the same state of 

 chemical decomposition which characterizes the rest of the interior of the 

 lode, nor do they show anything like the tendency to become metamorphosed 

 into clay, which is everywhere to be noticed in connection with the propylite 

 alterations. They are limited in size, as will be seen on Atlas-Plate 11, 

 and it is a very notable fact that they lie to the west of the andesite dike, 

 which shows them to be more properly portions of the west country, segre- 

 gated from the main rock by a simple sheet of clay; however, the west clay 

 so evidently surrounds them that they can but be considered as true horses. 



In the Potosi the immense quartz-body, which, south of the plane of the 

 old Potosi shaft, uninterruptedly fills the fissure, branches as it extends north- 

 ward, and includes two considerable masses of propylite. The longitudinal 

 dimensions of the westernmost are 700 feet, with a transverse width of 280 

 feet on the surface, and a greatest depth of 210 feet. North of this point the 

 great Virginia chamber is filled from the region of the ore-channel to the west 

 wall by a mass of propylite 800 feet across. This great horse terminates on 

 the north in the Gould and Curry, being cut out by the east quartz, which 

 swings across the lode and unites itself to the west wall. The bottom of this 

 horse is not yet reached ; for at the lowest works of the Savage and Hale and 

 Norcross mines there is still a considerable distance from the east quartz to 

 the west wall. As was shown when studying the details of this region, the 

 ore-channel, instead of being a gingle sheet of quartz, as is the case in the 

 Ophir and Gold Hill groups, here occupies a complicated zone of fissures, 

 and the masses of quartz and sheets of clay subdivide the propylite materials 

 of this zone into a group of horses, whose minute details of form can only be 

 understood by closely examining the sections. 



From the north point of the Gould and Curry through the Consolidated 

 claim, and even beyond the northernmost workings of the Ophir, the quartz 

 walls are separated by two remarkable horses. The longitudinal extent of 

 these masses is about 1,500 feet. The eastern one, which separates the Ophir 

 quartz from the red body, has an average breadth of 50 feet, and penetrates 

 into the lode from the surface to a depth of 580 feet; the western, or great 



