The oldest part of the formation, the Pryor Conglomerate, contains no Tenontosaurus fossils, and they only appear in the uppermost, most recent part of the Little Sheep Mudstone Member.
Najstariji dio te formacije, konglomerat Pryor, ne sadrži fosile Tenontosaurusa, a oni se pojavljuju samo u najgornjim, najnovijim dijelovima člana Little Sheep Mudstone.