MAZATZAL QUARTZITE 
299 
PROTEROZOIC MAZATZAL QUARTZITE OF CENTRAL 
ARIZONA 
By Eldred D. Wilson 
Arizona Bureau of Mines 
The Mazatzal Range lies in central Arizona, about fifty miles 
northeast of Phoenix. Between the Tonto and Verde River 
valleys it trends northwestward from the Roosevelt Dam. The 
massif of the range is composed almost entirely of schists, slates, 
and quartzites of Pre-Cambrian age, the sedimentaries being usual¬ 
ly disposed at high angles. The great succession of indurated 
sandstones to which the title Mazatzal Quartzite is here applied, 
constitutes the main part of the mountains from the central Mazat¬ 
zal Peak northward. There are, however, four separate and 
distinct areas of the quartzite. Besides the chief body of quart¬ 
zite, lying between the Mazatzal Peak and North Peak, there are 
extensive outcrops 25 miles to the north, in the vicinity of Natural 
Bridge, south of Pine postoffice; also 80 miles to the northwest 
of Mazatzal Peak, a short distance southeast of Del Rio and 
about 20 miles from Prescott, on the Santa Fe, Prescott and 
Phoenix railroad; and still a fourth is found just south of the 
Mogollon escarpment between Tonto and Cherry creeks, 30 miles 
to the northeast. Of the Pre-Cambrian complex the quartzite un¬ 
der consideration appears a lithologic unit entirely distinct from 
the schists. It is a hard, vitreous rock, light-brown to gray in 
color, fine-grained, and often cross-bedded, but possessing at vari¬ 
ous levels also many phases of conglomerate the subangular to 
rounded pebbles of which vary from very coarse sand to small 
boulder one-half foot or more in diameter. Occasionally there 
are lenticular layers of maroon-colored, gray-spotted, hard, 
arenaceous shales which frequently display ripple-marks and sun- 
