Pg. 21, 45, 47-49, 51. Sheridan sandstone. Is a peculiar rock, looking like an ordinary sandstone of various degrees of fineness and in its coarsest state a pebbly conglomerate. Color greenish gray to rather dull brown. When closely inspected it is found to be composed of soft and hard rocks, both rounded and angular --quartz and feldspar; jasper, slate, and argillaceous shale, green, red, and black; and fragments of fossils, corals, and crinoids, but particularly pieces of brachiopods of size large enough to recognize. Most conspicuous feature is the angular pieces of black slate, which at first suggest fragments of carbonaceous matter but are evidently fragments of the more ancient slates. Igneous materials also are associated with them, emphasizing their close association in origin with the tuffs and volcanic ash beds with which they are stratigraphically associated. Believed to be about the same age as Ashland shales and older than Ashland limestones. Fauna presents affinities with both Clinton and Niagara of New York. Is regarded as younger than Aroostook limestone. Age is Silurian.
Named from exposures on Sheridan Plantation, south of Aroostook River, Aroostook Co., northeastern ME.

Source: US geologic names lexicon (USGS Bull. 896, p. 1983).

Pg. 172-173, 174. Sheridan sandstone. Stratigraphic revision. Unit now considered younger than shales and limestones of Ashland formation. Age is Silurian.

Source: US geologic names lexicon (USGS Bull. 1200, p. 3574).

Pg. 8, 9. Sheridan sandstone. Name not used; preoccupied by a Precambrian unit in Yellowstone National Park.

Source: US geologic names lexicon (USGS Bull. 1200, p. 3574).

Pg. 16 (table 2), 31-33, pl. 1. †Sheridan formation. Authors propose name Frenchville formation to replace Williams' and Gregory's (USGS Bull. 165, 1900) Sheridan sandstone (preoccupied).
[See also entry under Frenchville.]

Source: Exerpted from US geologic names lexicon (USGS Bull. 1350, Frenchville entry p. 275).