Blakely Sandstone (Middle and Lower Ordovician) (AROb;0)

State	Arkansas
Name	Blakely Sandstone (Middle and Lower Ordovician)
Geologic age	Phanerozoic \| Paleozoic \| Ordovician-Early Ordovician-Middle
Original map label	Ob
Comments	Mostly grey shale (75%) with alternating beds of sandstone and minor conglomerate. Approximately 500 ft. maximum thickness.
Primary rock type	shale
Secondary rock type	sandstone
Other rock types	conglomerate
Lithologic constituents	Major Sedimentary > Clastic > Mudstone > Shale (Bed) Sedimentary > Clastic > Sandstone (Bed) Minor Sedimentary > Clastic > Conglomerate (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	Ferguson, J.G., 1920. Outlines of the geology, soils, and minerals of the State of Arkansas: Arkansas State Bureau of Mines, Manufactures and Agriculture,192 pp. Stone, C. G. and Bush, W. V. 1982, Summary of the geology of the eastern Ouachita Mountains, Arkansas: Guidebook - Arkansas Geological Commission, vol.82-2, 24 pp.
Geographic coverage	Garland - Montgomery - Pulaski - Saline