Named as the uppermost unit (of six) in the Greer division for the town of Delphi, Greer Co, OK in the South Oklahoma folded belt province. No type locality designated. Consists of white, drab, gray and sometimes yellowish persistent ledge-forming dolomitic limestone 1-5 ft thick (average 3 ft thick). Is arenaceous and soft at some localities and cavernous at other localities. Is exposed on hills of North Fork in Roger Mills Co, OK and on practically all the divides of Elm Fork, Haystack, Bull and Fish Creeks in Greer Co. Overlies a 20 ft thick unnamed red clay shale. Is older than the Quartermaster division (new). Permian age.

Source: GNU records (USGS DDS-6; Denver GNULEX).