48 SILVER-LEAD DEPOSITS OF EUREKA, NEVADA. 



various horizontal sections will show; but it is remarkable in this respect, 

 the irregularities nearly correspond on all the levels. 



Relations of the quartzite and secondary fissure. The motion of this qiiartzite Upward 



along the plane of its contact with the limestone has already been men- 

 tioned. It is a difficult matter to tell what has been the extent of the up- 

 ward motion, but that it has been very considerable is shown by the com- 

 minution of the quartzite and limestone at their contact, and the numerous 

 striation marks where either of these rocks have remained in a solid con- 

 dition. When the main fissure was made and the faulting took place which 

 raised that portion of country lying southwest of the fissure, the quartzite 

 was moved up, not only along the fissure, but also along the plane of its 

 contact with the limestone, and the limestone wedge between the quartzite 

 and the fissure slid back against the limestone hanging wall. The upward 

 motion of the quartzite crushed and otherwise dismembered the limestone 

 lying between it and the solid northeastern wall. When the fissure between 

 the quartzite and limestone reached a point southwest of the present Rich- 

 mond hoisting works, it shot off into the limestone instead of following 

 around the contact plane of these two rocks, which turns towards the south. 

 The continuation of this quartzite fissure is the fissure which is found in 

 the Richmond and Albion mines accompanying the narrow band of quartz- 

 ite, and which has been described in detail. The Ruby Hill fault fissure 

 lies much farther to the northeast, near the shale, and has also been de- 

 scribed in detail. The positions of these two fissures and their relations to 

 each other can be observed in the different maps and diagrams. They are 

 designated by heavy black lines. 



The manner in which the narrow band of quartzite found its way into 

 its present position seems to admit of but one solution, namely, that its oc- 

 currence is due to a succession of faulting movements which followed the 

 line of the accompanying fissure, and that it originally formed part of the 

 main body of quartzite which must here underlie the limestone. It is alto- 

 gether improbable that it constituted a distinct bed of quartzite laid down 

 upon the back limestone. In this case some indications of its existence 

 would have been noticed in other parts of Ruby Hill. It is not possible 



