ransome: the ray quadrangle 385 



ably composed of thin generally yellowish to rusty, worm- 

 marked, shaly quartzite indicative of a change in sedimentation 

 preparatory to the deposition of the succeeding Devonian lime- 

 stone. The most characteristic material of these upper beds 

 is a fine-grained, unevenly colored, pink and green quartzite in 

 layers an inch or two thick separated by films of olive-gray 

 shale, whose cleavage surfaces are ridged and knotted with 

 numerous worm casts. The most noteworthy features of the 

 thicker beds are their generally pebbly character, which is a use- 

 ful means of distinguishing isolated exposures of the Troy quartz- 

 ite from the, locally at least, pebble-free Dripping Spring quartzite, 

 and their conspicuous cross bedding. While the Dripping Spring 

 quartzite is arkosic the Troy quartzite shows little or no feld- 

 spar. In the Ray and Globe quadrangles the name quartzite is 

 generally apphcable to this formation, but farther north, near 

 Roosevelt and in the Sierra Ancha, it is essentially a sandstone. 



The average thickness of the Troy quartzite in the Ray quad- 

 rangle is estimated at 400 feet. 



General comment on preceding for7natio7is. The formations just 

 described, from the Scanlan conglomerate at the base to the 

 Troy quartzite at the top, constitute an apparently conformable 

 series. The name Apache group was applied to these beds in 

 the Globe report, although at that time the Troy quartzite was 

 not distinguished from the Dripping Spring quartzite and con- 

 sequently did not figure as an individual unit in the group. 

 Moreover, the Mescal limestone, supposed then to be above 

 all of the quartzite, was grouped with the Devonian and Car- 

 boniferous limestones of the ''Globe limestone." As revised 

 the Apache group now includes, from the base up, the Scanlan 

 conglomerate, the Pioneer shale, the Barnes conglomerate, the 

 Dripping Spring quartzite, the Mescal limestone, and the Troy 

 quartzite. 



No identifiable fossils have been foi^nd in the beds of the 

 Apache group, but from the facts that it underlies the Devonian, 

 overlies schists and granitic rocks, and appears to be equivalent 

 at least in part to the known Cambrian of the Bisbee District 

 and of the Grand Canyon, it is provisionally classed as Cambrian. 



