The superficial dermal elements are preserved, and the occiput is visible. The skull is clearly low, very broad, and short. With normal length of postorbital and orbital regions. The face is much shorter than any other pelycosaur except edaphosaurs. Lacrimal expanded laterally upper the canines. Maxilla contributes to the edge of the orbit as there is no lacrimal jugal contact in the orbit. The squamosal and postorbital are extensively in contact because the temporal opening is small and of oval shape. Also, because the cheek slants outward to very higher degree than is usual in pelycosaurs, the temporal opening is exposed in dorsal view. The premaxillae and nasals are short and the frontals are of moderate length. The supratemporal in "Eothyris parkeyi" is much more extremely developed than in any other pelycosaur. In "Eothyris parkeyi", the postorbital bone is probably the largest for any synapsid, with large lateral and dorsal portions to the skull roof. The slope from skull table to quadrate is gentle, due to shortness of skull. The quadratojugal is very long and jaw articulation is in line with the tooth row. Typical pterygoid flanges and slender are present back in the skull, below the anterior part of the temporal opening. The quadrate is on the right side and is exposed dorsally. The interparietal and tabulars occupy the dorsal rim of the occipital surface.