When did Coelophysis roam New Mexico?
Fossils of Coelophysis are found in New Mexico in rocks of Late Triassic age. These are rocks that are about 205 to 210 million years old. Geologists assign a Triassic age to these rocks because they contain fossils that are similar to those found in Triassic rocks in Europe, where the Triassic Period of the geologic timescale was first defined. The numerical ages (for Coelophysis: 205-210 million years ago) are based on analysis of volcanic ash beds that contain radioactive minerals that can be measured to estimate numerical ages.
