E. T. Wherry — New Occurrence of Carnotite. 577 



varies from none in the Australian to perhaps 6 molecules 

 in the Pennsylvania mineral, but then it must be remembered 

 that most of this material is amorphous, leaving the question 

 open as to its possible water content when well crystallized. 

 The mineral may therefore be provisionally admitted to that 

 group, which, named according to Washington's suggestion* 

 (with one modification, the retaining of -ite as a termination, 

 which, in the writer's opinion, may be desirable, to avoid con- 

 fusion with chemical terms), becomes : 



Uranite Group. 





R"(U0 2 ) 2 (R V 4 ) 2 .8II 2 ; chiefly 



orthorhombic. 



Autunite Ca (U0 2 ) 2 (P0 4 ) 2 .8H 2 0. 



Calcium phosphuranite 



Uranospinite . Ca (U0 2 ) 2 (As0 4 ) 2 .8H 2 0. 



" arsenuranite 



Torbernite... Cu (U0 2 ) 2 (P0 4 ) 2 .8H 2 0. 



Copper phosphuranite 



Zeunerite..-- Ca (U0 2 ) 2 (As0 4 ) 2 .8H 2 0. 



" arsenuranite 



Uranocircite . _ Ba (L r 2 ) 2 (P0 4 ) 2 .8H 2 G. 



Barium phosphuranite 



Carnotite (Ca,K 2 ) (TJ0 2 ) 2 (V0 4 ) 2 .XH 2 0. Calcium-potassium 



vanaduranile 



Geological Relations. 



Mt. Pisgah, the ridge extending westward from the Lehigh 

 River just north of the town of Mauch Chunk, represents a 

 synclinal mass of the Pottsville formation, the great series of 

 interbedded sandstones and conglomerates regarded as the 

 lowest member of the Pennsylvanian, overlying the Mauch 

 Chunk red shale, the top of the Mississipian.f The contact 

 between these formations, as exposed in the cuts of the high- 

 way and electric railroad across the eastern end of the ridge, is 

 not a sharp one, but shows interbedding of the two types of 

 sediment through a thickness of at least 100 feet. In addition 

 to the red shale, there are also small lenses of black shale in 

 the midst of the conglomerates. 



The carnotite occurs in scattered streaks and patches through- 

 out the lower portion of the conglomerate, not extending far 

 above the last red shale layer, although ledges of conglomerate 

 continue to be exposed 600 feet farther to the summit of the 

 ridge. As the road turns westward, gradually rising across 

 the beds, the layer containing it can be followed to a distance 

 of 2000 feet, but then disappears beneath the roadway, and no 

 trace of the mineral could be found at the corresponding hori- 

 zon where again exposed near Tamaqua, 10 miles further west. 

 Although its distribution is quite irregular, it is certainly most 



* This Journal, vol. xxxiii, pp. 137-151, 1912. 



\ For a full description of these formations see Stevenson. Bull. Geol. Soc. 

 Amer., vol. xiv, pp. 15-96, 1903 ; vol. xv, pp. 37-210, 1904. 



