INDURATED FOSSILIFEROUS AQUIA FORMATION ON CHESTER RIVER, 2 1/2 MILES BELOW CHESTERTOWN, KENT COUNTY.

Contains casts of large mollusks of Eocene age.

The text of the Folio states:

Character. The formation consists ordinarily of loose sand containing considerable glauconite, which in places makes up the body of the formation. Where the material is fresh its color ranges from light blue to dark green, but where it has been exposed to weathering for a considerable time it has assumed a reddish-brown to light-gray color. The beds are in most places unconsolidated, although some have become firmly indurated by iron oxide. Small well-rounded pebbles coated with iron oxide occur in a few places near the base of the formation. This gravel is exposed in several places in the region southwest of the quadrangle. Where the beds have been exposed to atmospheric action, as on divides, the iron in the glauconite has been segregated to form beds of iron sandstone, which are very numerous and in places have a thickness of 1 to 2 feet. Several exposures of the formation, showing these ferruginous segregations, are to be seen along Severn River. Opposite Rolphs, on Chester River, there is an excellent exposure of indurated fossiliferous weathered greensand. (See PL VI.) One layer of firm sandstone is about 10 feet thick.

The Folio also states:

Fossils. The Aquia formation in Maryland has yielded a varied fauna, but in the Tolchester quadrangle the variety is not so great as in the region southwest of Severn River. In addition to the fossils named in the above sections, Pecten choctavensis and P. dalli have been found along Southeast Creek. Elsewhere the shells are well preserved, but in the Tolchester quadrangle the shells have been practically removed by solution, and the fossils are in the form of casts and molds. (See PL VI.)

The fossils of the formation have been described and illustrated in the report on the Eocene issued by the Maryland Geological Survey in 1901.