﻿6 Bulletin 16 6 



on the history of the Mississippi embayment is at once interesting 

 and important. 



The age of the Woods Bluff sub-stage therefore marks the 

 greatest southern retreat of the Gulf's waters during the Eocene 

 era. For the Eower Claiborne seas began to make an inroad 

 upon the area now occupied by western Mississippi, and the 

 Jackson seas reached the region of Crowley's Bluff, Ark., or still 

 farther north. Again the sea or Gulf water was forced back and 

 the Vicksburg beds were deposited over an area strikingly similar 

 to that represented by the Woods Bluff deposits. 



Kind of sediment, meaning. — The character of the material 

 composing the Woods Bluff outcrop near Roberts is also well 

 worthy of remark. As a rule, naturally, the Tertiaries along this 

 Archaean border have derived their sediment from the quartz and 

 feldspars so abundant in the crystalline rocks close at hand. In 

 fact the Eocene beds of the eastern part of Georgia, save the 

 buhrstone beds, are composed of rather coarse sand and clays of 

 various kinds and colors, but especially of white or whitish de- 

 cayed feldspars resembling sometimes the purest kaolins. They 

 are wrought to a considerable extent in this State and South 

 Carolina. Not so with this Woods Bluff bed. Its origin is evi- 

 dently of a secondary nature or, at any rate, precisely the same as 

 that of the beds of the same age in southern Alabama and at 

 Sabinetown, Texas. This would lead to the inference that there 

 were currents capable to transport earlier Eocene and Cretaceous 

 materials along the shore or in shallow waters from, probably, 

 the Alabama region to central Georgia. 



Other Beds and Horizons. 



Grovetown. — So far as the general appearance of the lower 

 Tertiary beds are concerned, one has only to visit the vicinity of 

 Grovetown to form a fair idea upon the subject. To the north- 

 west of the railway, and perhaps one-half mile west of the resi- 

 dence of Dr. Hatton, one sees in the lowest stream basins sand 

 beds with much clay and many quartz pebbles. About and above 

 such places are at least 20 feet of similar arenaceous beds though 

 hardened, presumably by calcium carbonate. This whitish rock 

 is used for chimneys and a few other purposes. They seem to 

 contain no fossil remains. Above, however, from 10 to 30 feet 

 come stiff white clays with small bivalve shells and some Bryozoa. 



