Semi-Centennial Volume. 179 



writer's Algronkian formation includes the Pioneer shale and the Scanlon 

 congrlomerate and the Tapeats sandstone which lies between the shale 

 and the conglomerate in a few places. It should also be added that as 

 one approaches the Sierra Ancha the Tonto group undergoes slight 

 changes and many variations are noticed which only careful study of 

 detail work will straighten out. The writer's Tonto Sandstone group in 

 the Apache mountains is the Apache group of the Globe quadrangle with 

 the addition of the Troy quartzite and Mescal limestone, all of which 

 are Cambrian in age. Carboniferous and Devonian rocks also occur in 

 the Apache mountains but were not mapped, though their presence is 

 noted in the Nantan Mountains. 



In correlation, the Apache group in the Globe quadrangle, from base 

 up, includes the Scanlan conglomerate, Pioneer shale, Barnes conglom- 

 erate and Dripping Spring quartzite. Devonian and Carboniferou^s 

 limestone were also mapped in that region, as the "Globe limestone" 

 along with which was mapped the Mescal limestone in many places. The 

 Abrigo limestone of Bisbee and Tombstone is an equivalent of the Long- 

 fellow formation of Clifton, the Mescal limestone of the Globe-Ray quad- 

 rangle and at Roosevelt and in the southern part of the Sierra Ancha 

 (the Troy quartzite of the Globe-Ray region — 400 feet thick — is the white 

 quartzite — 8 feet thick — at the top of the Abrigo at Bisbee), and the 

 Mauv limestone (formerly included in the Tonto shale) and the Bright 

 Angel shale together of the Grand Canyon section. In this paper it will 

 be considered as the Mescal limestone. The Tapeats or Tonto quartzite 

 (sandstone) is an equivalent of the Bolsa quartzite of the Bisbee and 

 Tombstone sections, the Coronado quartzite of Clifton, the Dripping 

 Spring quartzite (or the Dripping Spring quartzite, Barnes conglomerate. 

 Pioneer shale and Scanlan conglomerate) of the Globe-Ray quadrangle 

 and Roosevelt region and the southern part of the Sierra Ancha. '^ 

 Below is my section "From Farmer's residence on Cibicu to Salt Springs 

 on Salt river, near its confluence with Canyon creek,"'"' compared with 

 the "Globe and Ray quadrangles."^*' 



14. See Ransonie, F. L., Professional Paper 98-K of the U. S. Geological Survey, 

 pp. 143, and 1(54-166, and plate XXV. 



l.j. Reasan, .\. B., Geologv of the Fort Apaclic resion in .\rizona. .Vin Geologist, 

 vol. 32, pp. 273-274. 



16. Ransome, F. L., loc. cit., plate XXV. 



Section from Farmer's residence on Section from the Globe and Ray quad 



Cibicu to Salt Springs on Salt river near rangles. 

 its confluence with Canyon creek. 



UPPER RED \V.\LL GROUP TORN.VDO LIMESTONE. 



(NOW SUPAI). 1,000 feet. 



1. AlternatinK limestone and sandstone Thick beds of light-gray limestone. Fos- 

 I'rodvctun rora. Spirifer. cameratus, C'ala- sils scarce in lower or Mississippian por- 



iiiileii cannaeformiM). 60 to 120 feet. tion. hut plentiful in the Pennsylvanian 



2. Millstone grit, calcareous sandstom- jiortion. 



shaly to massive. 20 feet. No recognizable plane of division be- 



Iweeii Mississippian and Pennsvlvanian. 

 LOWER RED WALL GROUP (NOW 



RED WALL). 



3. Alternating gray limestone and 

 shale varying in color from black to red 

 (OrthiM imrnntn, Orthis livia, S/iirifer fur 

 niriiln. .S'. strintiiM, S. pr^pxtenxiifi. S. I'^e- 

 mm. Ortlionnta iiaralletii Lit haul ration rati- 

 fornienxf, Choitetpx ilnlmnnia) . 400 feet. 



