The Sheep Pen Sandstone is a late Triassic geologic formation exposed in northeastern New Mexico.

[2] The formation consists of up to 33 meters (108 ft) of thinly bedded light brown sandstone.

[4] Ichnofossils (track fossils) have been found in thee different locations 10 kilometres (6.2 miles) north of Kenton, Oklahoma.

The lower site includes the invertebrates Scoyenia and the dinosauroid Grallator on a scour surface.

The ore took the form of chalcocite, malachite, and azurite, deposited both in lenticular beds and in clastic plugs.