About 225 million years ago, during the Triassic Peroid, New Mexico lay near the Equator. Dense tropical forests covered the river floodplains that crisscrossed the state. Conifers, ferns and cycadeoids comprised most of the vegetation.

These leaf impression from a Triassic lake bed south of Santa Fe are exceptionally preserved; carbon compressions represent most of the leaves. Fern and cycadeoids dominate the fossils and are characteristic plants that grew in New Mexico during the Triassic.