A Report on the Bauxite and Fullers' Earth of the Coastal Plain of Georgia
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1917 edition. Excerpt: ...of fullers earth and similar clays belonging to the Twiggs clay member of the Barnwell formation occur in a narrow belt extending more than half way across the State. The westernmost exposures are in Dooly County, and the belt continues northeastward to Savannah River near Augusta, with exposures in Houston, Crawford, Twiggs, Bibb, Bleckley, Wilkinson, Jones, Baldwin, Washington, Glascock, Jefferson, Burke, Richmond and Columbia counties. Throughout most of the area underlain by the Twiggs clay the underlying Ocala limestone and the earlier Eocene formations are absent, so the location of the outcrops is just south of the belt in which the Cretaceous strata come to the surface. Stratigraphic relations.--The Twiggs clay member occupies a position at the base and near the northern margin of the Barnwell formation, which consists principally of glauconitic sand and marl. The clay grades downward and southward into the Ocala limestone, or into the marl and oyster shell beds of the Barnwell formation. Along the northern margin of the outcrops it is overlain with a slight unconformity by red sands of the Barnwell formation. This unconformity is exposed at Pikes Peak and Grovetown, but it evidently represents a withdrawal of the sea for only a short distance and for a short period of time, because farther south the clay member is conformable with the remainder of the Barnwell formation. Northeast of Wilkinson County the Ocala limestone is absent, and the clay rests directly on the surface of the Lower Cretaceous, or is separated from it only by a thin bed of sand, and locally tongues of the clay member overlap the Cretaceous beds entirely and rest upon the crystalline rocks of the Piedmont area. The most notable of these overlaps are at Roberts...
- 189 x 246 x 6mm | 209g
- 13 Sep 2013
- United States
- black & white illustrations