SCIENCE. 



sixth, and seventh orders of magnitude, before those 

 of the third and fourth had been correctly computed. 

 This seems to be a sufficient reason for the nearly 

 stationary condition of the lunar theory during the 

 past three-quarters of a century, notwithstanding the 

 great efforts which have been made to perfect its solu- 

 tion. Its advancement has been blocked by the 

 obstacles thrown in its path by analysis itself; and 

 we may therefore reasonably hope for substantial im- 

 provement in the theory and tables when they are no 

 longer embarrassed with equations which have no 

 existence in nature." 



We may remark that there are two ways in which 

 the correctness of Mr. Stockwell's conclusions may be 

 tested : first, a mathematical expert competent to pro- 

 nounce upon his theoretic processes should go over 

 his work with the most searching criticism in every 

 detail; and second, his theory should be compared 

 with observations. But this latter would be a task of 

 such immensity that no astronomer unassisted would 

 hope for its completion. 



NEW YORK ACADEMY OF SCIENCES. 



Oct. 31, 1881. 



The President, Dr. J. S. Newberry, in the Chair. 

 Twenty persons present. 



The following paper was read by Mr. John H. 

 Furman : 



" The Geology of the Copper Region of Northern Texas 

 and the Indian Territory." 



The well-marked cretaceous beds of Parker County, 

 Texas, extend for 30 miles north of west from Weather- 

 ford, on the road to Graham. They consist of strata of 

 shelly limestone, sandstone and shaly clay, the latter gray- 

 ish or reddish in color. An occasional thin seam of soft 

 coal is found ; and the water is strongly impregnated with 

 lime. A stratum of sandstone stretches for thirty miles 

 N. W. from Fort Worth. In this rock springs are found 

 containing sodic carbonate, similar to the waters of the 

 artesian wells of Fort Worth, Tarrant County, at a depth 

 of about 270 feet. Towards Graham, the country as- 

 sumes a semi-mountainous appearance, and, for twenty- 

 five miles or more, sandstone ridges alternate with prairies, 

 the hills being covered with scrub oak. Some of the 

 ridges attain an elevation of two or three hundred feet 

 above the prairies. The strata are horizontal, and large 

 portions of the original surface have been carried away by 

 erosion. The upper stratum is in many places a conglom- 

 erate, made up of small pebbles. In this region the 

 seams of coal met with are generally soft, and the only 

 workable bed known is one about three feet thick, yielding 

 a fair quality of bituminous coal, which crops out and has 

 been traced for several miles near the Clear Fork of the 

 Brazos river in Young County. This supposed coal re- 

 gion has a general N. E. and S. W. direction. 



Approaching Graham the prairies begin to resemble the 

 plains ; and the ridges, capped with sandstone, show 

 bases of mottled reddish-colored shales, or clay ; salt 

 springs and salt streams are found, indicating the border 

 of the great alkaline region. From Graham to Fort Grif- 

 fin in Shackleford County, thence north in Throckmorton 

 County, the country rises. Every few miles a steppe is 

 mounted, the face of the escarpments showing horizontal 

 thin limestone strata. The same features continue, and 

 then the country slopes towards the Brazos river. 



Turning westward through Haskell County, the surface 

 lowers again towards the Brazos, the river coursing south 

 to north, and a plain is crossed, the ground differing from 

 any observed. The soil is mixed and covered with gravel, 

 in many places several feet deep. The pebbles vary in 



size from half an inch to an inch and 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 supposed veins of copper, a very short examina- 

 tion 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 occurrence. 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 cop- 

 per, usually two or three inches thick? Overlying this 

 stratum is a cap-rock of gypsiferous sandstone, about 

 three feet thick, with a layer y% to X ,ncn thick, impreg- 

 nated 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 cuprified wood and nuggets of iron pyrites. In 

 the wood the original structure in many instances is per- 

 fectly preserved, also appearing cuprified in all stages of 

 decay, as though it had become half rotten before the pet- 

 rifaction was effected. The overlying sandstone fre- 

 quently contains biscuit-like concretions of gypsum. Jun- 

 iper trees abound and also cover the gypsum 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 crys- 

 talline carbonate of copper, or with white gypsum, thus 

 appearing 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 cup- 

 riferous gray bed, and then through a succession of lay- 

 ers 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 oc- 

 casionally 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 of 

 Haskell County. 



At one point the gray bed lies between beds of sand- 

 stone ; the red bed does not appear, and the underlying 

 sandstone strata are almost white, laminated, and very 

 hard. The bed is more than two miles distant from the 

 gypsum hills ; the gravel drift is noticeable and even 

 abundant. Observing the nuggets of copper ore and the 

 drift pebbles lying about in places on the red bed, the 

 idea forced itself upon me that there might be a remote 

 connection between the two. However, the nuggets of 

 ore are evidently concretions, and no pebbles occur in the 

 gray bed. The gypsum range extends several miles 

 across, with a western declivity similar to that on the 

 eastern side. A plain, a little over one hundred feet be- 

 low, feaches beyond to the foot of the great Llano Esta- 

 cado. On these hills and on this western plain the 

 gravel drift is wanting. 



The copper bed was traced five miles further to the 

 north ; also in Knox county, not far from the Wichita 

 river, and forty miles or more north of the southern por- 

 tion of Haskell county, besides learning its supposed oc- 

 currence north of the Wichita river. The copper band 



