70 MINCsG INDUSTET. 



Ophir horse, more than three times the thickness of this, extends along the 

 west side of the red vein for 1,500 feet, and descends to a depth of 460 feet 

 beside the Virginia quartz. 



More than nine-tenths of all this horse material is of propylite, consisting 

 simply of immense slices cut off from the overlying country, and separated 

 from each other by parallel, longitudinal fissures. The great horses are shat- 

 tered through and through, but even in the lesser lines which subdivide them 

 may be traced, first, a general parallelism vdth the trend of the lode; and, 

 secondly, a tendency to break concentrically with the curves of the east wall. 

 The lesser of these horses rest frequently throughout their whole length in 

 quartz, but the larger ones invariably touch the west wall at one or two points, 

 and are sustained from falling laterally, by contact with each other and by 

 the solid walls. 



The fissure and horses together, for the one is a complement of the other, 

 .give a complete idea of the larger dynamical results. These long, thin wedges 

 have slid down on one another, and, crowding together, touch with their 

 lower edge the west wall. In this tremendous dislocation have been opened 

 seams and chambers, of which the larger have been filled with quartz and 

 the lesser densely packed with clay. Beside these larger horses no consid- 

 erable chamber of the vein is without its freight of small fragments. The 

 west quartz contains throughout its whole extent angular masses of syenite 

 and propylite, varying from the size of a hen's egg to a foot and more in 

 diameter. In these fragments there is not the least sign of decomposition. 

 The feldspars and hornblendes are perfectly preserved, the edges sharp as if 

 recently fractured, and every appearance compels the belief that they are quite 

 unaltered. This is the more remarkable, since they are found in a material 

 whose very existence in a fissure is proof of an aqueous if not solfataric origin. 

 These included fragments are usually the starting places of quartz crystalliza- 

 tions. They lie chiefly in the upper 300 feet of quartz, gradually diminishing 

 in frequency in depth. In the larger fissures toward the east, both those 

 which are filled with quartz and such as are chiefly lined with clay, may be 

 found immense numbers of small propylite fragments. Where quartz-bodies 

 in depth approach the contact of the two walls, or, in other words, as they 

 begin to thin toward their own termination, the quartz becomes more iind 



