The Carmel Formation is the oldest clearly Jurassic rock. It is clearly dated from the marine mollusk fossils found in the limestones and shales in the area near Zion National Park. Away from that area, the Formation is characterized by red or reddish brown mudstones or siltstones that contain no fossils. The origin of this layer varies with location, from mudflats in the central region near Canyonlands to a more streambed-laid character farther to the east.
An unusual characteristic of this formation is the extreme contortions found in the vicinity of Moab and Bluff, Utah. Apparently this distortion took place after the beds were laid down as part, but not all, of the Entrada Sandstone laid on top of the Carmel, is also distorted.
