UPPER COAL-MEASURES. i)3 



Upper Coal-measures.— Beds of this epocli iiret'ouiid (•(informal )ly ovci-lyiiij; 

 tilt' Weber couglomerate, their true geological jiositiou being adiniralily 

 shown at the head of Hunters Creek (athis sheet \m) in a belt of lime- 

 stone about one mile in length, west of the Welier conglomerate horizon. 

 Both series of rocks dip to the west at liigh angles, the limestones, 

 liowever, being cut off by a body of basalt which forms the mass of Basalt 

 Peak and the Strahlenberg. A much larger body of this limestone is found 

 forming the long uniform slope of Diamond Peak, altliough there its true 

 position is oljscured by longitudinal faults, which in places bring it in direct 

 contact with the Lower Coal-measures and in others it abuts unconforma- 

 l)lv against the Weber conglomerate. 



The thickness attained bv the rocks of this epoch is nowhere exposed 

 in the district, the overlying beds having either suffered removal by 

 denudation or else been concealed beneath flows of igneous rocks. West of 

 Diamond Peak a number of narrow valleys cross the limestone, but, as the 

 inclination of the ridge coincides closely with the dip of the beds, they 

 nowhere reveal any considerable thickness. The beds are estimated at oOO 

 feet. In the northern and central portions of the state of Nevada the Upper 

 Coal-measure limestones attain a development of nearly 2,000 feet. At 

 Moleen Peak,'ju.st soutli of tlie Huinl)oldt River, they are cstimatiMlar 1,X00 

 feet in thickness where tlicA' conformalily overlie a iieavy deposit of con- 

 glomerates in their essential features quite like the Weber conglonujrate of 

 Eureka. In the field the Upper Coal-measures may be distinguished readily 

 from the Lower Coal-measures by their lighter color and greater preva- 

 lence of fine grained beds. These colors are light bluish gray and drab, 

 the latter possessing a conclioiilal fracture and compact texture. These 

 compact limestones frecpientlv present forms of erosion (ptite different from 

 the coarse grained and granular limestones of the Lower (^oal-ineasures. 

 Throughout the horizon the limest(mes are interstratified with belts of grit 

 and siliceous pebbles, ludd together by a calcareous cement, in which are 

 intercalated thin beds of purer limestone. One or two jirominent beds are 

 apparently made up of ([uartz pebl)lesand fragments of an older limestone, 

 carrying such fossils as Fusil ina ci/lindrini and Produrtiis semircticalatm, 



' U. S. Geological Esi)li>ratii>u of tUo ForlietU Parallel, vol. 2, Ooscriptivo Ocolofiy, p. 600. 



