312 



IRVING. 



depth. In the Doyle vertical lateral enrichments occur and 

 also in the Metallic Streak Mine on the ridge south of Calam- 

 ity Creek. 



The ore is essentially a silicified mass of brecciated limestone 

 fragments, which are stained with iron oxide and which contain 

 calcite in the lower grade ores. The general run of ore, how- 

 ever, is hardly to be distinguished from the limestone except 

 that' it is very slightly darker and is very hard, being an almost 

 complete replacement of the limestone. Porphyry is not present 

 in these verticals. 



The line where the ore is cemented to the wall rock (see 

 diagram) is often clearly marked, but the structural details, such 



Siliceous <^o\a Ove ,,. 

 in VJme&t-one.. 



Fig. 20. Diagram in perspective to illustrate the character of the Ragged Top 

 Verticals. 



as banding etc., pass from the one into the other, and it is 

 only possible to tell them apart, from the slightly darker color 

 and greater hardness of the ore. The ore in the Metallic 

 Streak Mine, is often brilliantly stained with fluorite. No 



