178 
EDWARD STEIDTMANN 
Bass limestone—White crystalline limestone alternating with beds of argil- 
laceous and calcareous red shale containing sun cracks, 
cut by thick diabase sill. 
335 feet 
Hotauta conglomerate—Arkose conglomerate characterized by lack of sorting 
and transportation. 
o-6 feet 
erosion . 
Unconformity 
Rests on an even surface of 
Detailed study of the Vishnu series is lacking, but it is thought 
to be equivalent to the Pinal schists of the Bisbee district. 
Paige reports that the pre-Cambrian rocks of the Silver City 
folio of southwestern New Mexico are granites with minor quartzitic 
and schistose masses, the whole being mapped as a unit. 
Patton? ef al. state that the pre-Cambrian rocks in the Alma 
district of Park County, Colorado, consist mostly of granitic and 
banded gneisses and acid schists, granites, pegmatites, and aplites. 
Ransome? presents ten Paleozoic sections ranging from southern 
to northern Arizona. 
above pre-Cambrian. 
are as follows: 
District 
Bisbee 
Tombstone 
Clifton 
Globe and Ray quadrangles 
Roosevelt 
Southern part of the Ancha district 
Northern part of the Ancha district 
In each section Cambrian is unconformably 
The pre-Cambrian rocks in these sections 
Pre-Cambrian Rocks 
Pinal schists (sericitic schist chiefly 
metamorphosed sediments cut by 
granite) 
Pinal schist and gneissic quartz-mica 
diorite 
Pinal schist and granite 
Pinal schist and intrusive granitic 
rocks 
Granite 
Granite 
Granite, older pre-Cambrian schists, 
younger pre-Cambrian quartzite, 
and conglomerate 
1Sidney Paige, “Description of the Silver City Quadrangle, New Mexico,” 
U.S. Geol. Surv., Atlas Folio No. 199 (1916), 19 pp., 4 pls., 17 figs. 
2H. B. Patton, A. J. Hoskins, and M. G. Butler, “Geology and Ore Deposits of 
the Alma District, Park County, Colorado,” Colorado State Geol. Surv. Bull. No. 3 
(1912), 284 pp., 29 pls., 6 figs. 
3 F. L. Ransome, ‘“‘Some Paleozoic Sections in Arizona and Their Correlation,” 
U.S. Geol. Surv. Prof. Paper 98 (1916), pp. 133-66, 8 pls., 4 figs. 
