Either Pennsylvanian or very early Permian. See University of Texas Bulletin, no. 1753 (Apr. 20, 1917). Professor Udden's Section No. 7, bed no 8 (p. 28-34). On page 29 this bed is referred to the Baptonian (= Penn.) and elsewhere (p. 42) he refers it to Wolfcamp (= Permian). All the fossils from a place formerly known as Wolfcamp (located on Udden's map) about 30 miles northwest of Marathon, Texas. [3654] DOCUMENT NO. 124 Invertebrate Paleontology Yale Peabody Museum [3694/1] cm 1993