Mesilla Valley Shale
| Mesilla Valley Shale | |
|---|---|
| Stratigraphic range: | |
| Type | Formation |
| Underlies | Mojado Formation |
| Overlies | Muleros Formation |
| Thickness | 210 feet (64 m) |
| Lithology | |
| Primary | Shale |
| Location | |
| Coordinates | 31°47′39″N 106°32′35″W / 31.7940792°N 106.5430513°W |
| Region | New Mexico |
| Country | United States |
| Type section | |
| Named for | Mesilla Valley |
| Named by | W.S. Strain |
| Year defined | 1976 |
The Mesilla Valley Shale is a geologic formation in southern New Mexico, northern Chihuahua, and far west Texas. It preserves fossils dating back to the Albian age of the early Cretaceous period.
The formation is particularly well exposed at Cerro de Cristo Rey, near El Paso, Texas, where it is part of a thick sequence of uplifted Cretaceous beds that record transgressions (advances of the sea onto land) and regressions (retreats of the sea from the land) of the Western Interior Seaway during the mid-Cretaceous.