Abstract

The Triassic and Jurassic Systems are represented in the Henry Mountains by a varied assemblage of dominantly continental beds. These can be classified in several natural sedimentological groups according to dominant types of rock and environments of formation: (1) The Early Triassic Moenkopi Group, (Black Dragon, Sinbad, Torrey, and Moody Canyon members) chiefly redbeds of marginal marine and deltaic origin, about 400 ft thick; (2) The Chinle Group, (Moss Back, Shinarump, Monitor Butte, Petrified Forest, Owl Rock and Church Rock members) consistituting a variegated assemblage of continental rocks with an aggregate average thickness of about 800 ft; (3) The Glen Canyon Group, (Wingate, Kayenta, Navajo-Page) dominantly cross-bedded sandstone, Wingate and Navajo are generally considered to be of eolian origin, thickness about 1300 ft; (4) The San Rafael Group, (Carmel, Entrada, Curtis and Summerville formations) dominantly marginal marine with both eolian and subaqucous facies, thickness about 1500 ft; (5) Morrison Formation, (Salt Wash and Brushy Basin members) fluvial and lacustrine, thickness about 550 ft. The Chinle and Morrison formations are important sources of uranium in the Henry Mountains.