Pg. 179, 180. Hart School bed. A limestone bed (2 to 6 feet thick) in Sedwick limestone member of Moran formation (of Cisco group), occurring 3 to 12 feet below top of Sedwick member. It is of yellow color and characterized by abundance of small silicified gastropods and other fossils. [Several detailed sections of Moran formation show Sedwick member as consisting of 2 to 6 limestone beds, chiefly yellow, but in some places blue in lower part, varying in thickness from 1 to 6 feet, separated by shale beds varying in thickness from 1 to 19 feet. See also entry under Sedwick.]
Outcrops on road at Hart School, in sec. 2969, T.E. and L. survey, 6 mi north of Putnam, [Callahan Co.], Brazos River region, central northern TX.
[The Moran formation is now (ca. 1936) included in Wichita group.]

Source: US geologic names lexicon (USGS Bull. 896, p. 919, Sedwick entry p. 1949-1950).