Ellsworth formation. Yellow-brown sandstone and reddish or varicolored shale mostly nonmarine. Thickness 25 to 200 feet. Includes Rocktown sandstone above and Terra Cotta shale below. Unconformable below Solomon formation (new) and above Belvidere formation. Age is Cretaceous (Comanche).
[Type locality not designated. Origin of name not stated.] Probably named from occurrences in vicinity of Ellsworth, Ellsworth Co., central KS.
[According to D.F. Merriam, 1963 (Kansas Geol. Survey Bull., no. 162, App. B, Catalog of Mesozoic nomenclature for Kansas), name appears on a chart (Moore, 1935) with no explanation except that classification of Dakota beds is in doubt awaiting completion of studies by A.C. Tester; later the name appeared on the Geologic Map of Kansas (Moore and Landes, 1937). Plummer and Romary (1942) credit the name to Tester as appearing on Moore's chart.]

Source: US geologic names lexicon (USGS Bull. 1200, p. 1242); supplemental information from Kansas Geol. Survey Bull., no. 162.

Ellsworth formation of Dakota group. Mapped with Dakota group. Age is Late Cretaceous.

Source: US geologic names lexicon (USGS Bull. 1200, p. 1242).

Pg. 153. [†Ellsworth formation abandoned.] Dakota formation, as herein defined, contains stratigraphic units formerly called "Rocktown channel sandstone," "Ellsworth formation," "Solomon formation," "Reeder sandstone," "Marquette sandstone," "Spring Creek clay," and others.

Source: US geologic names lexicon (USGS Bull. 1200, p. 1242).