1883. 19 Trans. N. Y. Ac. Set. 



ing vein has yet been opened. The following localities were re- 

 ferred to ; the vein at Bristol, Conn. : the Schuyler Copper Mine 

 at Belleville, N. J. ; many points along and on the east side of the 

 Alleghany belt, and in the Rocky Mountains, both on their east 

 and west slopes ; deposits which have been worked, though with 

 little success, as well as the concretionary ore and copper replac- 

 ing wood in the Indian Territory, New Mexico, etc. These latter 

 indicate an extraordinary impregnation of a shallow sea, in which 

 the Triassic strata were deposited, and the copper was thrown 

 down in association with salt and gypsum. It is a question, yet 

 unsolved, why these Triassic rocks were so impregnated with cop- 

 per. Toward the old shore of this sea, more and more silver was 

 thrown down with the copper, until near the margin, at Silver 

 Reef, its quantity became sufficient for working. The deposit of 

 these ores appeared to be one of the accompaniments of the ex- 

 trusion of the trap. 



In reply to inquiries by Profs. Hubbard and Martin, the 

 President further stated that masses of native copper sometimes 

 occurred, but usually only scales, rarely pieces up to a half pound 

 in weight ; and that ores containing even as low an amount as five 

 or six per cent, of copper have been profitably worked. 



In the Eastern States, the impregnation of the Triassic rocks 

 with copper was apparently one of the results of the eruptions of 

 trap through them, and the copper was perhaps derived from the 

 Archaean rocks below, which contained much copper, brought up 

 dissolved in hot water. In the West, the copper was probably con- 

 tained in the drainage of the old lands which formed the shores of 

 the shallow Triassic sea, and was precipitated by evaporation. 

 Near the Wasatch Mountains, the western boundary of the Trias, 

 the copper was associated with considerable silver, as at the Silver 

 Reef Mines, and both metals were probably derived from the 

 leaching of the old land which occupied portions of Utah, Nevada, 

 etc., and which in ancient as well as modern times was a region 

 rich in ores. 



A number of curious crystals of calcium carbonate, apparently 

 calcite, with hexagonal form, found in clay, at Laramie City, were 

 then exhibited by a member, Mrs. Weld. 



