STRUCTURE OF RUBY HILL. 45 



exactly what point on this latter level the quartzite begins to thin out, but 

 an alteration in its width is first noticeable about 800 feet westerly from the 

 shaft. (See Plate XIII.). Here the quartzite is but a few feet thick, and a 

 short distance farther to the west it is but a few inches, being scarcely more 

 than a seam filled with quartzite, limestone, and clay. This character it 

 retains in the continuation of this level, varying in thickness from a few 

 inches up to 20 feet or more until the extreme northwest workings in the 

 Albion ground are reached. Near the point where this thinning out of the 

 quartzite is noticed there are unmistakable signs of a fault. This fault is 

 of no great lateral extent, and forms one of a series of similar faults which 

 are found in this narrow strip of quartzite at various points on the different 

 levels. These faults have a general northerly course, and dip sometimes 

 easterly and sometimes westerly. What has been the extent of the faulting 

 in a vertical direction cannot be determined with any certainty, but in 

 some cases it has been considerable. At the point mentioned above, there 

 are two slips; but it is the one which has a westerly dip of 85° that seems 

 to displace the quartzite. One hundred feet beyond this point a drift has 

 been run into the "back lime," as the limestone is called which lies on the 

 southwestern side of this narrow strip of quartzite. 



In proceeding along the fourth level from the shaft, the main body of 

 quartzite is left at some unknown point, the explorations that have been 

 made in the back lime not having been sufficient to discover it, and the 

 narrow band that is followed is but a splinter from the main mass. On the 

 Richmond fifth level the quartzite is to be found at two points. The first is 

 about 200 feet south of the shaft, and the second is at the end of the first 

 southwest cross-cut. In both places it appears to be the main solid body. 

 Still it is possible that at the last point it may be only 50 feet thick, for it 

 is found no wider than that on the sixth level 100 feet below and some little 

 farther west. The explorations on the sixth level (Plate XIII.) lay bare the 

 contact of the quartzite and limestone for a long distance. The end of the 

 long southwest cross-cut, which is called the fissure drift, reveals the same 

 fault in the quartzite that is exposed on the fourth. In the southeasterly 

 branch of this southwesterly fissure drift the quartzite is found to be 50 

 feet thick. It is faulted and brought down to a seam by the fissure which 



