Trans. X. V. Ac. Set. 20 



Oci. 31, 



These mountains have the same general appearance as the Reeky 

 Mountains, which pass through the western portion of Texas and the 

 State of Coahuila, Mexico ; and it has been a matter of much interest 

 to observe that similar drifts of local origin are frequently met in the 

 latter regions. The Wichita Mountains appear to be identical in origin 

 with the Rocky Mountains, and constitute the most eastern spur of 

 that system. In Northern Mexico short ranges are encountered, strik- 

 ing east and west, and of these the Wichita Mountains appear to be a 

 reproduction. The Wichita Mountains will be found to contain mineral 

 deposits, possibly of some value ; veins of copper ores do exist 40 miles 

 west of Fort Sill, near Otter Creek, in the mountains ; but I am con- 

 vinced that the copper bed or stratum of Northern Texas will prove 

 of no commercial importance. 



DISCUSSION. 



Prof. Newberry remarked that the communication of Mr. Furman 

 was of great interest, since no accurate description had before been 

 given of the geological structure of the region where the copper occurs 

 in northern Texas and the Indian Territory. He had received speci- 

 mens from that region long ago and recognized their similarity to the 

 copper ores of New Mexico, where in the upper portion of the Triassic 

 formation copper forming concretions and replacing wood occurs in 

 many localities, and has been more or less mined for. In one locality 

 near Abiquim very extensive galleries have been cut in the sandstone 

 in search of copper which there replaces branches and trunks of trees 

 and forms concretions which are irregularly scattered through the rock. 

 Here the work was done by the early Spanish explorers perhaps 200 

 years ago, and the remains of the furnaces in which the copper was 

 smelted are still to be seen at the mouth of the mine. Still further 

 w'est, in southern Utah, the same formation carries copper and con- 

 siderable silver, at Silver Reef enough to pay well for mining, but in 

 no locality yet known are the deposits of copper ore sufficiently concen- 

 trated and continuous to make mining for that material profitable ; so it 

 would doubtless be found in Texas and the Indian Territory. The 

 copper was deposited with the Triassic rocks from a shallow sea in 

 which an unusual quantity of copper was held in solution. This im- 

 pregnated the sediments found at the bottom, replacing wood and 

 forming as nodules about some nucleus. The aggregate quantity of 

 copper in this formation was enormous, but, except where by the erosion 

 of the beds it accumulated at the surface and could be picked up with- 

 out any expense in mining, it would hardly pay to attempt to obtain 

 it by ordinary mining processes. 



The wood replaced by copper, Dr. Newberry said, was undoubtedly 

 all coniferous, and different from any now living. The beds which 

 contained the cuprified wood also contained much that was silicified. 

 Of this he had examined many specimens under the microscope and 

 had found the peculiar dotted cells which are characteristic of the con- 

 iferse, and these grouped in such a way as to prove the trees to have 

 belonged to the Araucarian group of conifers. So far as yet known 

 the angiosperms, or higher order of plants, did not maRe their appear- 

 ance on the earth's surface until after the copper bearing rocks of the 

 southwest had been depofited. 



