APPENDIX C. 



MINERALOGY. 



REPORT ON THE MINERALS COLLECTED : BY PROF. CHARLES 

 UPHAM SHEPARD. 



Amherst College, June 1, 1853. 

 My Dear Sir : The following report relates to the specimens collected 

 by Captain Marcy, and which, agreeably to your request, were submitted 

 by me to a chemical and mineralogical examination. 

 Very respectfully and truly yours, 



CHARLES UPHAM SHEPARD. 

 To President Hitchcock. 



1. COPPER ORES MARCTLITE. 



The most interesting of these was a specimen of rather more than one 

 ounce in weight, from the main or south fork of Red river, near the 

 Witchita mountains. It is a black compact ore, strongly resembling 

 the black oxide of copper from the Lake Superior mines, for which 

 substance I at first mistook it. It was partially coated by a thin layer 

 of the rare and beautiful atacamite, (muriate of copper of Phillips) 

 This is the first instance in which this species has been detected in 

 North America. On subjecting the black ore to a close investigation, it 

 proves to be a substance hitherto undescribed, and it affords me much 

 pleasure to name it, in honor of the very enterprising and successful 

 explorer to whom mineralogy is indebted for the discovery, Marcylite. 

 It is massive and compact ; fracture even ; color black ; opaque ; lustre 

 none ; hardness equals that of calcite, or 3 of the mineralogical scale ; 

 sectile streak shining ; powder light grayish black ; specific gravity, 

 4.0 to 4.1. In small fragments it melts in the heat of a candle, to the 

 flame of which it imparts a rich blue and green color. This is especially 

 striking when a blow-pipe is employed. The slightest heat of the in- 

 strument suffices for the fusion of the ore. The chloride of copper is 

 volatilized, and spreads over the charcoal support, from which the splen- 

 did green color rises also. On directing the flame of the candle against 

 it, the mass, or assay, remains for some time fluid, continuing to give 

 the color as at first, till finally the green and blue tinge declines, and at 



