CAHABA COAL FIELD: GENERAL DESCRIPTION. 17 
they dip back southeast at an angle of 60 degrees. In all 
these cases the Cambrian measures on the south and south- 
east side of the fault have a slope or dip to the southeast 
rarely greater than fifty or sixty degrees near the fault, and 
much less than that a short distance away from the fault, 
Along the interior fault, the same thing may be noticed, as 
for instance, along the line of the South and North Alabama 
Railroad near Helena, where the Wadsworth seam at the 
North “Y” has a dip to the southeast of 42 degrees, while 
immediately adjacent to this towards the northwest and just 
across the line of the fault the measures stand vertical, and 
beyond these vertical measures, which are here about a 
quarter of a mile wide, we come to the Wadsworth seam 
again, carried up by this upthrow to the much steeper 
dip of 50 or 60 degrees to the northwest. And even along 
the subordinate faults, such as the Piney Woods, we find the 
measures north of the fault dipping at an angle of 80 de- 
grees north, while those to the south of the same, dip only 
35 degrees to the south. 
This displacement of two miles vertical along the great 
boundary fault, and the complete overturn of a strip of 
country nine miles in length by over a mile in width west 
of Montevallo, bear witness to the tremendous force that 
has been brought to bear against the Cahaba Coal Field. 
The Cahaba Field is in the counties of St. Clair, Jefferson, 
Shelby, and Bibb ; the northeastern end being in St. Clair 
county, the southwestern end in Bibb, and the middle por- 
tion in Jefferson and Shelby. The county lines according 
to recent changes, are shown on the accompanying map. 
The rate of dip of the measures of the Cahaba Coal 
Field varies from flat or perfectly level up to sixty degrees 
from the horizontal. The wide part of the field contains 
the largest amount of flat measures. In the Lolley and 
Montevullo Basins you can travel for miles and find it very 
difficult to decide (judging by the eye) as to which way the 
measures are dipping. The Blocton Basin holds a large 
area of flat or level measures ; and the same is true of the 
Dry Creek Basin, and the north end of the Henryellen 
Basin. ; ; ; 
The measures on the southeast side of the interior fault 
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