. sero, sete | et 
oS 
Conclusions from the Sedimentary Record. 125 
ing which the transporting power of the streams was gradually 
diminishing and the surface approaching baselevel at a con- 
stantly decreasing rate. This great mass of calcareous sediment, 
part of which is a mechanical deposit, points to erosion of ex- 
tensive limestone areas which must have been in the Appa- 
lachian valley; hence the character of the formation siipports 
the conclusion reached from other evidence, that the drainage 
of that region was southward during the whole of the Cre- 
-taceous cycle. Passing the Rotten limestone, the curve leaves 
the horizontal axis, and in the Lignitic reaches its farthest 
distance therefrom, marking a period of high land or steep slopes 
and rapidly cutting streams. From this point it rapidly de- 
scends through the Buhrstone and Claiborne to the Vicksburg 
ic 
2 #4 3 
= Cate 
=o os 2 
i < 2 L 
iS) : Oo) = Pa 
Bays wires) og : oH ne Z 
eo) ail ais 5) ai ea = 
‘4 — ~ . - 
es o @ = 2 = B = id 
4S = 8 = 2 = 2 = 5 
> = io! 5p 2, ‘SI rr =) n 
4 cy S = = ° te) =) =] 
> Oo 4 ia] =| oS co A 
Eocene. Cretaceous. 
Fiaure 3.—Diagram showing variation in Character of Cretaceous and Tertiary 
Sediments in Alabama. 
limestone, showing a rapid decrease in carrying power of the 
streams and a near approach to baselevel in the valleys. . 
It is thus seen that during the time covered by the sedimentary 
record in southern Alabama there were two periods in which 
the land stood high and the streams were rapidly degrading the 
surface, and that these alternated with two periods in which 
the land was low, approximately at baselevel, and the streams 
carried little sediment, but were degrading the surface by solu- 
tion. Hence two baselevel peneplains separated by a considera- 
ble uplift are to be sought in the region from which the sedi- 
ments were derived. The two already described fulfill all the 
theoretical conditions, and the correlation of these peneplains, 
from other considerations, with Cretaceous and Tertiary time is 
