The Orr and Patterson sandstones occur in the Trace Creek Shale Member, Bloyd Formation, in surface exposures on the northern Arkansas structural platform. The Orr sandstone exhibits regional thickening trends to the south and southeast into the Arkoma Basin as shown by isolith maps for the area studied. The depositional environment that formed this sandstone comprised fluvial or deltaic channels feeding a destructive delta system to the southeast. The Patterson sandstone lies stratigraphically above the Orr sandstone, and is confined essentially to Franklin and Johnson counties. It is poorly developed or not present in Washington and western Crawford Counties. The Patterson occurs as a sand build-up formed by a lobate constructive delta system in the north of the area studied but thins to the south.
Corbin, Michael E.
"Geometry and Depositional Systems of the Orr and Patterson Sands, Bloyd Formation (Pennsylvanian), Eastern Franklin and Western Johnson Counties, Arkansas,"
Journal of the Arkansas Academy of Science: Vol. 32
, Article 12.
Available at: http://scholarworks.uark.edu/jaas/vol32/iss1/12