STRUCTURE OF RUBY HILL. 41 



shaie in the Albion. — A large part of the work which has been done in the 

 lower levels northwest of the A C° line has been performed by the Rich- 

 mond company. 



On this end of the hill the shale does not present any remarkable feat- 

 ures. Its contact with the limestone is irregular, as usual, but its position 

 underground conforms very nearly with that which it occupies on the sur- 

 face, always allowing for the dip of the formations. There are occasionally 

 masses of it intruded in the limestone. South of the Albion shaft it is in 

 close proximity to the quartzite, touching it in places. The quartzite referred 

 to is a narrow belt of quartzite, which will be described hereafter. The 

 shale is shown in the various horizontal sections, and it retains its general 

 relations to the limestone down to the deepest point west of the A C line, 

 namely, at the end of the ninth level of the Richmond. 



From limestone. — The time and manner of formation of the Ruby Hill fault, 

 and its subsequent filling either with rhyolite or clay, are matters of very 

 great importance as regards the history of the mineralization of the lime- 

 stone between the quartzite and the fault-fissure and the prospects of find- 

 ing ore either at a greater depth or by prosecuting developments in the 

 so-called front limestone. This body of rock lies northeast of the main 

 fissure, and although it has in many places the appearance of the ore-bear- 

 ing ground has hitherto been found unproductive, all the ore having been 

 obtained from the limestone wedge between the main fissure and the quartz- 

 ite. It is true that the prospecting done in the front limestone has not been 

 sufficient to prove that it contains no ore bodies, but it has been sufficient to 

 discourage search in that direction. It shows at any rate no such outcrops 

 as were apparent in the Champion, Buckeye, and Tip-Top claims (the orig- 

 inal locations of the Eureka Consolidated and Richmond companies), situated 

 in the southeastern slope of Ruby Hill, just above the quartzite and lime- 

 stone contact. If the theory, which will be discussed hereafter, is correct, 

 namely, that the ore was brought up in solutions from below through the 

 main fissure, the barrenness of the front limestone is easily accounted for 



"The A C line is parallel to the compromise line, and is the dividing line between the Richmond 

 and Albion ground, which was established by the courts in the suits between the two companies. Prior 

 to the fixing of this line the Richmond company had explored a large portion of the ground which is 

 now held by the Albion. 



