San Rafael Group | |
---|---|
Stratigraphic range: | |
![]() San Rafael Group on the east side of the San Rafael Swell. Entrada at the base, overlain by the Curtis, then Summerville, and capped by the Morrison (Tidwell and Salt Wash Members). | |
Type | Group |
Underlies | Morrison Formation |
Overlies | Glen Canyon Group |
Thickness | 490 meters (1,610 ft) |
Lithology | |
Primary | Sandstone |
Other | Mudstone, limestone |
Location | |
Coordinates | 39°10′26″N 110°27′58″W / 39.174°N 110.466°W |
Region | Four Corners |
Country | United States |
Type section | |
Named for | San Rafael Reef |
Named by | Gilluly and Reeside |
Year defined | 1928 |
The San Rafael Group is a geologic group or collection of related rock formations that is spread across the U.S. states of New Mexico, Arizona, Utah and Colorado. As part of the Colorado Plateau, this group of formations was laid down in the Middle Jurassic during the Bajocian, Bathonian and Callovian Stages.[1]