The Early Jurassic Epoch is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic–Jurassic extinction event, 201.3 Ma, and ends at the start of
Massive cliffs in Zion Canyon consist of Lower Jurassic formations, including (from bottom to top): the Kayenta Formation and the massive Navajo Sandstone
Cast of Plesiosaurus macrocephalus, a possible rhomaleosaurid, and perhaps a juvenile of Thaumatodracon