86 Scientific Intelligence. 



marcasite, bismuthinite, perhaps famatinite, and a new cupric 

 sulpkantimonite, which has been named goldfieldite. (See below.) 



The most notable features of these ore bodies are their remarkable 

 richness and their equally remarkable irregularity. The ores are 

 associated with craggy outcrops of silicified volcanic rock. 

 Associated with the silicification other processes of locally intense 

 alteration, especially the formation of alunite, have also been 

 active. The deposits have formed along irregular and branching 

 zones of Assuring. The surface ores were oxidized and furnished 

 a large part of the gold during the first years of exploitation. 



Goldfieldite occurs as a gray material in a dark telluric 

 crust found at the Mohawk mine. The material was crushed and 

 picked over under a lens. The gray portion appeared homo- 

 geneous, with the exception of a few minute specks of gold. 

 Color, dark lead-gray, with a high metallic luster. Brittle. Con- 

 choidal fracture. Hardness = 3 — 3*5. No crystal faces noted. 

 Analysis by Palmer on small amount of material gave : 



Cu S Te Sb As Bi Au Ag Gangue 



33-49 21-54 17-00 19*26 0'68 6*91 0*51 0*18 2*00 =101*57 



* 



The mineral is considered to be a cupric sulphantimonite, in 

 which part of the antimony is replaced by arsenic and bis- 

 muth and part of the sulphur by tellurium. Formula derived is 

 5CuS.(Sb,Bi,As) 2 (S,Te) 3 . 



It would seem, in view of the. facts presented concerning this 

 substance, that the giving to the material a name and rank as a 

 new species is hardly warranted. The material was intimately 

 mingled with other minerals and had to be crushed and picked 

 over by hand, so that the purity of the material analyzed must be 

 somewhat questioned. It showed no crystal forms. The analysis 

 was made on a small amount of material, and shows a high sum- 

 mation, and the formula derived is only approximately justified 

 by the analysis. It would seem desirable that more positive 

 proof should be given before we can assume the existence of 

 such an unusual compound as a cupric sulphantimonite. 



w. E. F. 



3. United States Geological Survey ; Issue of Geologic Folios 

 in pocket form. — The Geological Survey has recently inaugurated 

 the publication of an edition of the Folios of the Geologic Atlas 

 of the United States in octavo form convenient for field use. 

 The maps are folded and enclosed in a pocket so that the whole, 

 including the accompanying text, forms a pamphlet of about 

 6x9 inches. The folio form will also be continued, as it is most 

 satisfactory for office and library use, but the new pocket edition 

 will be welcomed by those at work in the field. The Folio now 

 received is No. 167 of the series, and describes the Trenton, New 

 Jersey-Pennsylvania Quadrangle ; it is stated that the five folios, 

 No. 164-168, have been printed and are ready for distribution in 

 this new form. It is also to be noted that henceforth the 

 separate maps, unfolded, showing the areal geology of the 



