Tratis. N. V. Ac. Set. 20 Oct. 31, 



the mountains extends to the south and southeast. It is found as far 

 west as the Haskell County copper bed, and as far east as the Archer 

 County copper bed is known. The river channels of that section of the 

 country have been formed since this drift period. The development of 

 the Wichita Mountains seems to have marked the close of a period ot 

 uplift and simultaneous erosion. 



These mountains have the same general appearance as the RocKy 

 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 OHgin 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 ; ve'ns 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 Abiquiui 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 

 west, 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 oresuffic'ently 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 



