712 DESCRIPTIVE GEOLOGY. 



allied to Carboniferous types, and, but for its occurrence witli cliaracteristic 

 Star Peak or Alpine Triassic fossils, would be regarded, at least, as an indi- 

 cation of Palaeozoic rocks. In speaking of the S. alia, Messrs. Hall and 

 Whitfield say,^ "We know of no species of Spirifera or Spiriferina in rock of 

 this age resembling the one under consideration, or with which it can be 

 confounded. The substance of the shell, like all those from the same 

 locality, is badly exfoliated, and has apparently undergone some change, 

 which has, to some extent, obliterated the natural features, so that we are 

 not able to say definitely if it be punctate or not, consequently are in some 

 doubt in regard to its generic relations." 



From the same formation near Dun Glen, Professor Gabb^ has described 



the following species: 



Nautilus multicameratus. 



Ammonites Homfrayi. 



Mytilus Homfrayi. 



MyopJioria alta. 



Bhynclwnella aqviplicata. 



Mining operations have been carried on in several places along the 

 Pah-Ute Range, but with little practical success, except perhaps in the 

 region of Dun Glen, where there are a number of well-defined prominent 

 veins, more or less worked, in general striking north and south, and dipping 

 west in conformity with the structure of the range. A number of narrow 

 quartz veins, known as the "Munroe series", situated a short distance 

 southeast from Dun Glen, have attracted considerable attention from their 

 3^ielding a relatively large amount of free gold and almost no silver; a rare 

 occurrence in Central Nevada, where the ores are mainly sulphurets of 

 silver and lead and their associated products of decomposition, the gold- 

 bearing veins being limited to a few localities like the "Munroe" and "New 

 Pass Mines" in the Desatoya Mountains. In both these districts, however, 

 active mining operations soon ceased, and the occurrence of so much free 

 gold presented more that is of mineralogical and geological interest than 

 of practical value. 



1 Volume iv, 282. 



'^ Geological Survey of California, Palaeontology, vol. i, 18G4. 



