bckel.] ALABAMA. 73 
In this middle division of the Selma formation the fossils are rarer 
lan in either of the others, oysters and anomias being the most eom- 
non forms. This variety of the rock forms the bluffs along Alabama 
liver from Elm Bluff up to Kings Landing. It is seen in its most 
ypical exposure at White Bluff, where it is at least 200 feet in thick- 
ess and makes on the right bank of the river an almost perpendicular 
>ank. On Tombigbee River- it extends from near Bartons Bluff past 
femopolis up to Areola and Hatchs Bluff. Its lowermost beds, a 
ompact limestone of great purity, form the upper parts of Bartons 
nd Hatchs bluffs. On Little Tombigbee River the same rock makes 
le celebrated bluffs at Bluff port and at Jones Bluff (Epes), beyond 
mich for several miles it is shown along the stream. 
Judging from the width of its outcrop, this division of the Selma 
mlk must be about 300 feet in thickness. It underlies the most fer- 
le and typical " prairie" lands of the South. At intervals through- 
ut this region the limestone rock appears at the surface in what are 
nown as " bald prairies," so named from the fact that on these spots 
lere is no tree growth. The disintegration and leaching out of the 
mestone leaves a residue of yellowish clay, which accumulates some- 
mes to a thickness of several feet in low places. This cla}^ is used at 
le Demopolis plant in the manufacture of cement, and in most locali- 
es where suitable limestone is found the clay is present in sufficient 
Liantity to supply the needs of the cement manufacturer. 
At the base of this middle division occurs a bed consisting of several 
dges of compact, hard, pure limestone, which weathers into curious 
lapes, and has received the names horse-bone rock and bored rock, 
his bed, as above mentioned, appears at the top of Hatchs Bluff; also 
; Areola Bluff, and between Demopolis and Epes, at Jordans Ferry, 
id other places. Where it outcrops across the country it makes a 
dge easily followed and characterized by the presence on the surface 
': loose fragments of the limestone. 
The lower part of the formation, like the upper, is composed of 
ayey limestone, in many places being rather a calcerous clay. The 
•lor is dark gray to bluish, and in most exposures there is a striping 
le to alternate bands of lighter-colored, purer limestone. Along 
labama River the strata of this division are seen in the bluffs from 
ings Landing up to Selma and beyond. On Warrior River they are 
en in the bluffs at Areola, Hatchs, Millwood, and Erie, in the last- 
,med locality occupying the upper part only of the bluff. On the 
pmbigbee, the bluffs at Gainesville, Roes, and Kirkpatricks are 
rmed mainly of the rocks of this division, while above Roes, at 
>rdans, occurs the line of junction with the middle division. Near 
is line of division a very characteristic feature is seen at many 
ints. About 10 or 15 feet below the hard ledges of pure limestone 
rming the base of the middle division the dark-colored argillaceous 
