The Collier Shale is a geologic formation in the Ouachita Mountains of Arkansas and Oklahoma. Dating from the Late Cambrian to Early Ordovicianperiods, the Collier Shale is the oldest stratigraphic unit exposed in Arkansas. First described in 1892,[2] this unit was not named until 1909 by Albert Homer Purdue in his study of the Ouachita Mountains of Arkansas.[1][3] Purdue assigned the type locality to the headwaters of Collier Creek in Montgomery County, Arkansas, but did not designate a stratotype. As of 2017, a reference section for this unit has yet to be designated.
^ abcdefRepetski, John; Ethington, R. (1977). "Conodonts from graptolite facies in the Ouachita Mountains, Arkansas and Oklahoma". Syposium on the Geology of the Ouachita Mountains. 1: 92–106.
^ abcdefghijklmnopqrsHart, William; Stitt, James; Hohensee, Steven; Ethington, Raymond (May 1987). "Geological implications of Late Cambrian trilobites from the Collier Shale, Jessieville area, Arkansas". Geology. 15 (5): 447–450. doi:10.1130/0091-7613(1987)15<447:giolct>2.0.co;2.
^ abcStitt, James; Rucker, John; Boyer, N.; Hart, William (May 1994). "New Elvinia Zone (Upper Cambrian) trilobites from new localities in the Collier Shale, Ouachita Mountains, Arkansas". Journal of Paleontology. 68 (3): 518–523. doi:10.1017/s0022336000025890. S2CID133418468.
^ abcdefghijHohensee, Steven; Stitt, James (November 1989). "Redeposited Elvinia Zone (Upper Cambrian) trilobites from the Collier Shale, Ouachita Mountains, west-central Arkansas". Journal of Paleontology. 63 (6): 857–879. doi:10.1017/s0022336000036544. S2CID133364723.