The correlation of the Vicksburg group - Tapa blanda

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1923 Excerpt: ...which are common in all the divi48297--23 3 sions of the Vicksburg group. There are different forms, however, but whether these are due to different stages in development the condition of the specimens does not show clearly. What seem to be the young of this species have a pointed apertural end in specimens consisting of two or three chambers only. Others seem to be rather rotund from the beginning, and it may be that these two represent different species. Polymorphina gibba occurs at the following U. S. G. S. stations: Byram calcareous marl.--Byram, Miss., 6454 and 6455; Vicksburg, 8240; Brandon, Miss., 7389; Leaf River, Miss., 7376; Woodward, Miss., 6648; Waynesboro, Miss., 6649. Glendon limestone.--Vicksburg, Miss., 6446; Robinson's quarry, Miss., 6548; Tiger Hill, Miss., 7735; McGowans Bridge, Ala., 6749. Typical Marianna limestone.--Castleberry, Ala., 6732 and 6734; Perdue Hill, Ala., 6729; Millry, Ala., 6702; St. Stephens, Ala., 6710 and 6711; Fail, Ala., 7214; Heidelberg, Miss., 6645; Tallahala Road, Ala., 7375; Brandon, Miss., 7371; Calmar, Miss., 7445. Mint Spring calcareous marl member.--Vicksburg, Miss., 6447, 6448, and 6451; Browns Cave, Miss., 7671; Boice, Miss., 6647. Red Bluff clay.--Hiwannee, Miss., 6456 and 8752; St. Stephens Bluff, Ala., 6713; Fail, Ala., 7213. Polymorphina byramensis Cushman. Plate V, figures 1-5. Polymorphina byramensis Cushman, U. S. Geol. Survey Prof. Paper 129, pp. 94,131, pl. 17, figs. 2a, 2b, 1922. Test short and broad, triangular, composed of a few chambers, usually only four, all except a final fifth chamber extending back to the base of the proloculum, forming a truncate test; chambers inflated; sutures deep and distincl; surface smooth; aperture radiate, only slightly produced. Maximum length 0.75 millimeter. Th...