78 



makes on the right bank of the river an almost perpendicular 

 bluff. On Tcmbigbee River it extends from near Barton's 

 Bluff past Demopolis up to Arcola and Hatch's Bluff. Its 

 lowermost beds, a compact limestone of great purity, form the 

 upper parts of Barton's and Hatch's Bluffs. On Little Tom- 

 bigbee River the same rock makes the celebrated bluffs at 

 Bluffport and at Jones Bluff (Epes), beyond which for several 

 miles it is shown along the stream. 



Judging from the width of its outcrop, this division of the 

 Rotten limestone must be about 300 feet in thickness. It 

 underlies the most fertile and typical "prairie" lands of the 

 South. At intervals throughout this region the limestone 

 rock appears at the surface in what are known as "bald prair- 

 ies," so named from the circumstance that on these spots there 

 is no tree growth. The disintegration and leaching cut of the 

 limestone leaves a residue of yellowish clay, which accumulates 

 sometimes to a thickness of several feet in low places. This 

 clay is used at the Demopolis plant in the manufacture of ce- 

 ment, and in> most localities where suitable limestone is found 

 the clay is present in sufficient quantity to supply the needs of 

 the cement manufacturer. 



At the base of this middle or Demopolis division occurs a 

 bed consisting of several ledges of compact, hard, pure lime- 

 stone, which weathers into curious shapes, and has received 

 the names horse-bone rock and bored rock. This bed, as above 

 mentioned, appears at the top of Hatch's Bluff ; also at Arcola 

 Bluff, and between Demopolis and! Epes, at Jordan's Ferry, and 

 other places. Where it outcrops across the country it makes 

 a ridge easily followed and characterized by the presence on 

 the surface of loose fragments of the limestone. 



The lower part of the formation (the Selma division), like 

 the upper, is composed of clayey limestone, in many places be- 

 ing rather a calcareous clay. The color is dark gray to bluish, 

 and in most exposures there is a striping due to bands of light- 

 colored, purer limestone alternating with the prevailing quality. 

 Along Alabama River the strata of this division are seen in 

 the bluffs from King's Landing up to Selmai and beyond. On 

 the Warrior River they are seen in the bluffs at Arcola, Hatch's, 

 Millwood, and Erie, occupying in the last-named locality the 

 upper part only of the bluff. On the Tombigbee, the bluffs at 

 Gainesville, at Roe's, and Kirkpatrick's are formed mainly of 



