Cambrian beds, northwest from stage road 2 miles south of Pioneer Mountain, Ray quadrangle, the bold hill on the left is composed, in ascending order, of diabase, Troy quartzite, Martin limestone and Tornado limestone. Gila County, Arizona. 1911.

Cambrian beds, northwest from stage road 2 miles south of Pioneer Mountain, Ray quadrangle, the bold hill on the left is composed, in ascending order, of diabase, Troy quartzite, Martin limestone and Tornado limestone. The broad saddle to the right of this hill is occupied by a great diabase sill, which passes beneath the Troy quartzite to the left and laps up onto a dip slope of the Dripping Spring quartzite just to the right. The diabase has disrupted the Mescal limestone, which belongs between the two quartzites and remnants of the limestone strata included in the diabase can be recognized as rather extensive white patches that in the field contrast sharply with the dark olive tint of the diabase surface. Gila County, Arizona. 1911. [...]