Cason Shale and Fernvale Limestone (Upper Ordovician) and Kimmswick Limestone, Plattin Limestone, and Joachim Dolomite (Middle Ordovician) (AROcj;0)

State	Arkansas
Name	Cason Shale and Fernvale Limestone (Upper Ordovician) and Kimmswick Limestone, Plattin Limestone, and Joachim Dolomite (Middle Ordovician)
Geologic age	Phanerozoic \| Paleozoic \| Ordovician-Middle Ordovician-Late
Original map label	Ocj
Comments	Carson Shale-calcareous shale with minor phosphatic sandstone (20 ft.); Fervalle Limestone-massive fossiliferous limestone (125 ft.); Kimmswick Limestone-massive bioclastic limestone (55 ft.); Plattin Limestone-micritic limestone intercalated with limey mudstone and dolomite (250 ft.); Joachim Dolomite-dolomicrite (150 ft.). Approximately 600 ft. maximum thickness. Summary-70% limestone, 25% shale, 5% sandstone.
Primary rock type	limestone
Secondary rock type	shale
Other rock types	sandstone
Lithologic constituents	Major Sedimentary > Carbonate > Limestone (Bed) Minor Sedimentary > Clastic > Mudstone > Shale (Bed) Incidental Sedimentary > Clastic > Sandstone (Bed)
Map references	Haley, B. R., Glick, E. E., Bush, W. V.; Clardy, B. F.; Stone, C. G.; Woodward, M. B., Zachry, D.L., 1993, Geologic Map of Arkansas: U.S.Geological Survey Special Geologic Map. Scale 1:500K
Unit references	Craig W. W, Wise, O, and McFarland, J. D. III,1984, A guidebook to the post-St. Peter Ordovician and the Silurian and Devonian rocks of north-central Arkansas: Guidebook - Arkansas Geological Commission, vol.84-1, 49 pp.
Geographic coverage	Baxter - Independence - Izard - Lawrence - Marion - Newton - Searcy - Sharp - Stone