Cretaceous synonyms

At Duba some limestones may belong to the Lower Cretaceous.

Westward to Houston and southward to about 32° 48' on the Alabama boundary and occupying a much larger area than the other Cretaceous formations, is the Selma chalk, called "Rotten Limestone" by Hilgard; it is made up of a material of great uniformity, - a soft chalky rock, white or pale blue, composed chiefly of tenacious clay, and white carbonate of lime in minute crystals.

The latest Cretaceous is the Ripley formation, which lies west of the northern part of the last-named, and, about Scooba, in a small strip, the most southerly of the Cretaceous - it is composed of coarse sandstones, hard crystalline white limestones, clays, sands, phosphatic greensands, and darkcoloured, micaceous, glauconitic marls; its greatest thickness is about 280 ft.

Deposits of the Tertiary period form the basis of more than half the state, extending from the border of the Cretaceous westward nearly to the Yazoo Delta and the Mississippi Bottom, and southward to within a few miles of the Gulf coast.

The high land in the west of the island and the somewhat less elevated region in the east are formed of Upper Tithonian and Lower Cretaceous limestones, the latter containing Rudistes.