MAZATZAL QUARTZITE 
305 
The Natural Bridge area shows the most complete section of 
the Pre-Cambrian quartzite, and also presents the best exposures 
displaying its relationships with both the older and younger rocks. 
In the canyon of Pine Creek is an exposure beginning just south 
of the Mormon Village of Pine, and extending southward for about 
six miles to a point five miles north of the junction of Pine Creek 
with the East Verde River, or about two and one-half miles south 
of Natural Bridge. This latter place is a popular ranch, or sum¬ 
mer resort, situated near a picturesue natural arch of recent 
travertine that has grown across the gorge of Pine Creek by 
deposition from spring waters issuing from the Red wall limestone. 
The Pre-Cambrian quartzite is exposed in this region to an areal 
extent of about 8 square miles in such a manner that, even when 
viewed on the map, it seems to project out of the Paleozoic sedi¬ 
ments and Tertic volcanics. 
This apparent anomally is easily understood, when the general 
stratigraphic and structural relations are considered; for, as al¬ 
ready mentioned, the Paleozoics abut the old hills of Pre-Cambrian 
quartzite. Furthermore, the region has undergone orogenic dis¬ 
turbances during both Pre-Cambrian and Post-Paleozoic times. 
Those of the latter were 'considered to be of an extent negligible 
for the purpose of this investigation; but those of Pre-Cam¬ 
brian date gave rise to the tilted, major fault-block which is so 
prominent today. The beds of this rock strike, near the south¬ 
ern edge of the area, about 50° northeast-southwest, and dip 
about 50° northwest; but, towards the northern edge of the area, 
the strike becomes almost north-south, and the dip gradually flat¬ 
tens out. This is probably due to Pre-Cambrian transverse fault¬ 
ing of the major block. 
Due to the nature of the old uneven surface, the Tapeats sand¬ 
stone is for the most part absent in the Natural Bridge region; 
however, there is usually between the Pre-Cambrian rocks and the 
true '‘Redwair’ limestone a member which in different localities 
varies between limestone, sandstone, and arkose, that might some¬ 
times be mistaken for the Tapeats formation. Whether this al¬ 
ways represents merely the base of the “Redwall” limestone, oc 
sometimes the Tapeats sandstone as well, is difficult to say. The 
