80 GEOLOGICAL REPOliT. [1F123, 124 



is but slightly undulatii g) there is a gradual ascent ; we first strike several 

 small Orange Sand ridges, then ascend a high one, on which Clear Spring P. 0., 

 (Dr. Kilgore's) is situated, and which divides the waters of the lloulka and 

 Chuckatonche frc in those of the Tibby. — The general section of the cretaceous 

 formation in this latitude (Fig. 2 of Tab. I.) will convey a better idea of the 

 general structure of the country, than could be given in words. It was neces- 

 sary, of course, to exaggerate the dips and elevations in this profile ; hence the 

 prairies, which to the eye seem level, here appear as a slope. 



123. The western slope of Kilgore's rklge is thickly covered with Orange 

 Sand, so that wells 70 to 80 feet deep are dug in the same, yielding freestone 

 water. But as we approach the eastern slope, we observe on the hillsides a 

 terrace gradually ascending, on top of which the Orange Sand appears thinner 

 and finally disappears on the crest, on which, as well as on the eastern slope 

 itself, to its foot, large patches of bald prairie, strewn with Exogyra and Ory- 

 pluxeae, Ostrea falcata and Placuna scabra, are of constant occurrence ; they 

 are frequently destitute of any soil whatsoever, appearing at a distance like 

 fields of snow. — This ridge preserves its S, E. and N. W. course, terminating 

 at the S., where the Chuckatonche and Tibby meet; northwestward from Kil- 

 gore's, it may be traced up to Houston, skirting on the W. a gently undulating 

 tract of oak uplands. Cretaceous outcrops arc abundant on its crest and eastern 

 slore up to where Heed Creek breaks through it, in the N. E. corner of T. 

 15, R. 3 E.; beyond, few are to be seen — the ridge becomes lower, and termi- 

 nates in the Flatwoods N. W. of Houston. — On the eastern summit of this 

 ridge, a well has been bored by Mr. William T. Dexter, S. 16, T. 15, R. 4 E., 

 in which at about 500 feet he passed through the Rotten Limestone into ledges 

 of hard rock alternating with water-bearing beds of loose micaceous sand with 

 shells — probably of the Tombigbee Sand group. Similar beds continued up to 

 650 feet, several streams of water being struck, but without raising the water 

 higher than 150 feet from the surface. When last heard of, the well remained 

 at the above depth, but will, it is to be hoped, be further pursued, since accord- 

 ing to the wells at Aberdeen, water would probably rise to within available dis- 

 tance of the surface, whenever the beds corresponding to those which supply 

 the Aberdeen wells should be reached, at 800 to 850 feet. This well is of some 

 interest, as from its location on the highest point of the outcropping stratum, it 

 is likely to afford reliable data in relation to its total thickness. 



12 k The prairies on the eastern slope of this ridge form part of the western 

 branch of the prairie belt which, beginning in S. E. Pontotoc, as above men- 

 tioned, extends its main body, (with scolloped edges, and an average width of 

 about five miles) to the southward, between the Chuckatonche and Tombigbee — 

 between whose waters it forms a dividing plateau — to Tibby Creek. The sur- 

 face of the prairie has a gradual ascent towards the east, as may be perceived in 

 the high hills and bluffs which skirt the Tombigbee on the W. side, and whose, 

 highest points, generally speaking, are nearly on a level with the surface of the 

 prairie. The western branch, (or rather perhaps succession of patches), which 

 leaves the main body below Okalona, after crossing the Chuckatonche and 



