278 THE JOURNAL OF GEOLOGY. 



widening to a maximum, where exposed, of three and a half 

 feet. On the west slope of the knoll the ore bed is not seen at 

 all, the only trace of it being an occasional black stain or dend- 

 rites in the limestone along the line where it should outcrop if it 

 extended through to this side. The bed also thins out to the 

 north and south, the whole length of the outcrop being only 

 about 400 feet. East of the outcrop of the ore, the knoll is cut 

 sharply off, as shown in Figure 2, by a rocky area which separ- 

 ates it from the mountains. It will thus be seen that the amount 

 of ore here is limited, and it is probable that the area under- 

 lain by it does not cover more than a few acres. 



Beneath the ore bed, as seen in one of the small pits that 

 have been made on the deposit, the calcareous material is soft 

 and partakes of the nature of a marl, while above, it is often 

 much harder and has in many places become coarsely crystal- 

 line. The crystillization seems to have taken place in spots in 

 the bed, and frequently bodies of crystalline material are sur- 

 rounded by, and blend into a massive and softer tufa of the same 

 composition. 



The fragments of sandstone, shale and gray limestone found 

 in this deposit are of the same nature as the beds of those rocks 

 which comprise the mountain to the east and are undoubtedly 

 derived from them. The pieces of limestone are so markedly 

 different from the calcareous bed enclosing them that they can- 

 not be confounded with it. The rock fragments are of unequal 

 distribution in the deposit, both laterally and vertically, sometimes 

 composing almost half of it, and sometimes being almost entirely 

 absent. They vary from a fraction of an inch to several inches 

 in diameter and are indiscriminately mixed. 



The age of the rocks composing the part of the Havallah 

 Range lying east of the manganese deposit is represented as Star 

 Peak Triassic on the map accompanying the Survey of the Forti- 

 eth Parallel.' As shown in the section given above they are 



^ U. S. Geol. Exploration of the Fortieth Parallel ; Clarence King, Geologist in 

 charge ; Vol. I., Systematic Geology, map III., Pre - Mesozoic and Mesozoic Expo- 

 sures. See also report of Arnold Hague, Vol. II., Descriptive Geology, page 680. 



