SI. 



1 • Trans. N. V. Ac. Sci. 



vary in size from half an inch to an inch atul a half in diameter, and 

 consist of feldspar, quartz, porphyry, and basalt. On the western side 

 of Haskell County the copper bed is reached not far from the Brazos 

 river ; and west of the copper a great belt of gypsum hills, several miles 

 in width, extends northward, parallel with the copper bed, into the 

 Indian Territory. Gypsum occurs there in most of its forms, including 

 selenite which has been locally mistaken for mica. 



On reaching a scene of attempted mining operations in search of sup- 

 posed veins of copper, a very short examination convinced me that no 

 vein would ever be discovered. Denudation has laid the bed bare, 

 sweeping away the larger portion uncovered and leaving only patches ; 

 but these were sufficient to give a clear conception of the mode of occur- 

 rence. The copper-bearing stratum is an ashy-colored clay shale, more 

 or less tinged with green, the upper portion showing the deep green 

 carbonate of copper, usually two or three inches thick. Overlying this 

 stratum is a cap-rock of gypsiferous sandstone, about three feet thick, 

 with a layer }i \.o }i inch thick, impregnated with carbonate of copper, 

 as though it had soaked it up from below. Underneath the gray or 

 green bed an intensely red clay shale is generally found. Nuggets of 

 copper are scattered over the surface of the red bed, with pieces of cu- 

 prified wood and nuggets of iron pyrites. In the wood the original 

 structure in many instances is perfectly preserved, also appearing cupri- 

 fied in all stages of decay, as though it had become half rotten before 

 the petrifaction was effected. The overlying sandstone frequently con- 

 tains biscuit-like concretions of gypsum. Juniper trees abound and also 

 cover the gvpsum hills, the perfectly preserved cuprified wood, with its 

 knots and bark, showing a fac-simile of that growth. I found in the 

 gray bed fragments of wood partially unaltered, as though it had just 

 commenced to absorb copper; also large pieces of coal, three or four 

 inches or more in diameter, the cracks of the same piece being filled 

 with crystalline carbonate of copper, or with white gypsum, thus appear- 

 ing veined with copper and gypsum. In parts of the bed remaining the 

 resemblance to piles of ashes and charcoal is strikingly deceptive. In 

 one shaft, sunk to a depth of about thirty feet, the horizontal position 

 of the strata was confirmed, the shaft passing through the gupriferous 

 gray bed, and then through a succession of layers of red shale and soft 

 red sandstone, in which not a trace of copper was found. The gray 

 stratum extends seventy-five feet or more under a point of the gypsum 

 hill. In a tunnel traversing this stratum I noticed occasionally pebbles 

 belonging to the gravel drift. This copper formation has a general 

 north and south course, usually less than fifty yards in width, and was 

 traced for a distance of eight or ten miles to the southern boundary ol 

 Haskell County. 



