Arizona republican., 1916-11-23

strata show along the Stoneman Grade as 1t ascends the mountain, and can be seen in greater thickness, probably not less than 5000 feet, by ascending Queen Creek further to the southwest. Sev- eral miles further southwest, towards the Gila, the same series of limestones crop out in mountain masses, pitching at a higher angle eastward, and in some of the upper beds Spirifers have ! been found, which I refer to the Coal Measure series of the Carboniferous formation. In some places there is a large development of coarse con- glomerate of a red color.
 Above the limestone at the King Mountain, as one dominates the { highest summit above the mine, the volcanic outflows which form the cap ping, consists largely of pitchstone porphyry carrying obsidian, geodes of quartz crystals. masses of chalcedony and of semi-opal.
 1 Below the limestone and quartZite serles, gneissic and hornbendic rocks of the Archaean age crop out and ap- pear to be the foundation rocks on which the sediments rest uncomform- ably. Still lower down the slope the rocks become sientic and are then re- placed by a distinctly formed feldspar
 
 crystals, and an abundance or iron py- rites finely disseminated. The forma- : ttion appears to have the position of a tdike. cutting the other rocks, but 1t is extensive, and continues to and be- yond the Silver King Mine. Ii may be regarded as the enclosing rock of the tSilYer King, though in one place, some t200 feet above the mine, there is a strongly defined outcrop of dense, hard porphyry with hornblende cegs- tals and brilliant glassy feldspar form | ing sientic porphyry.
 The geology and mineralogy of the great developed mining districts of
 Final County might be included in one great belt lying on the western and southern slopes of the Pinal noun i tains The formations of these dis tricts. of which there are two, the Ray Christmas Copper belt and the Mag ma Silver King belt however, show different characteristics. Therefore. 1 for technical reasons it were better to divide the region into the two distinct districts
 GEOLOGY OF THE RAY DISTRICT 1 The Copper Camp of Ray occupies the valley of Mineral Creek, a tribu- tary of the Gila River The valley was formed by a synclinal fold, having a general direction of north twenty de- grees west The slopes of the valley have a general inclination of about thirty degrees from the horizontal, rising gradually from an elevation Of 2000 feet above sea level at the creek, | bv steps due to faulting. to an cleva- i tion of about 1900 feet above that point.
 The ore bearing formation. which is a disseminated deposit of copper in schist, covers both slopes of the valley to a depth of several hundred feet. On the west slope this bed of schist Is ex- posed on the surface where being sub 7 jected to weathering and oxidation. the upper portion has been leached of the values and forms a capping to the un- deriving ore bearing portion This de- posit is being mined on a vast scale | by the Ray Consolidated Copper Com pany
 On the east slope the copper bear ! ing schist is capped by flows of da 2 | cite and thin beds Of later sedimen- This condition is due to extensive ! taries to a depth of about 200 feet l This condition is due to extensive { faulting which has lowered the eastern section of the bed below that on the western slope The superimpOsed po- sition on the western slope. exposed this section to erosion resulting in the
 removal of dacite capping while the eastern section gave greater resistance | to these forces.
 i The boundary between the eastern and western sections Is distinctly marked by the upturned edge of the massive daoite flow along a great fault which is parallel to the creek. giving ! the impression of the outcrop of a ! dikc.
 NATURALIZATION Crushing and faulting of the schist ! bed has resulted in the formation of a system of points and fractures. sc minutely complete. that ore deposition along these has amounted practically