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



Art. XLVII. — A New Occurrence of Carnotite'* by 

 Edgar T. Wherry. 



Introduction. 



The more or less definite bright yellow uranium-vanadium 

 mineral known as carnotite lias been heretofore observed at a 

 number of points in western Colorado and eastern Utah,f and 

 as an alteration product of " davidite," a rare-earth-bearing 

 rutile, at " Radium Hill," South Australia. J The purpose of 

 the present paper is to call attention to its occurrence near 

 Mauch Chunk, Carbon County, Pennsylvania. 



In Genth's Mineralogy of Pennsylvania! autunite was 

 stated to " have lately been found in a conglomerate from 

 the neighborhood of Mauch Chunk," the exact locality being, 

 however, unknown. Specimens labeled similarly are included 

 in several of the old collections of Pennsylvania minerals, but 

 a study of these and of a considerable quantity of material col- 

 lected at what is probably the original locality, the eastern 

 end of Mt. Pisgah, immediately north of the town of Mauch 

 Chunk, has shown that the mineral in question is really to 

 be classed as carnotite. 



Although the locality was re-discovered, by accident, by 

 the writer in 1908, and the nature of the mineral proved by 

 qualitative tests, detailed study was deferred in the hope of 

 obtaining more satisfactory material when opportunity should 

 present itself for thorough examination of the deposit. As this 

 hope has not been realized, in spite of exhaustive search, it 

 was decided to proceed with analysis of the specimens on hand, 

 and to publish an account of the occurrence. 



General Description. 



The mineral presents the form of an amorphous to minutely 

 crystalline bright yellow coating or impregnation in a conglom- 

 erate, often penetrating cracks in the quartz pebbles. Micro- 

 scopic examination shows it to be quite impure, containing 

 much limonite and clayey matter, and even the most crystalline- 

 looking specimens show only an occasional translucent rectan- 

 gular flake, with straight extinction, suggesting the tetragonal 

 or orthorhombic system. 



* Presented at the Baltimore meeting of the A. A. A. S., 1908 ; abstract 

 in Science, vol. xxix, p. 751, 1909. 



f Hillebrand and Eansome. Bull. U. S. Geol. Survey, No. 262, pp. 9-31, 

 1905 ; Fleck and Haldane. Kept. State Bur. Mines, Colorado, 1905-06, pp. 

 47-115. 1907; Gale, Bull. U. S. Geol. Survey, No. 315, pp. 110-117, 1907; 

 Bull. No. 340, pp. 256-262, 1908. 



% Crook and Blake, Mineralogical Magazine, vol. xv, pp. 271-284, 1910. 



§ Report B, 2nd Penna. Geol. Survey, p. 144, 1874. 



