OAHABA OOAL FIELD: HELENA BASIN. 49 
tinuing thence along the outcrop of the seams you will pro- 
ceed for nearly two miles on measures that have an un- 
broken regularity, but at the north end the outcrops curve 
around in a shape much like a fish hook, as shown on the 
accompanying map; this portion of the basin lies very reg- 
ular and is well worth the attention of the capitalist and 
miner. The measures in the southwest end of this basin 
also curve around in the same fish hook form that they 
have at the northeast end, as shown by the outcrops of the 
Helena and conglomerate seams on the accompanying map. 
The outcrops at both ends of the basin were located by a 
special instrumental survey by myself. 
The causes resulting in the disturbances and irregularity 
in the measures of this basin are discussed in chapter I, 
giving the general description of the whole field. Most of 
the outcrops of the seams of this basin have been carefully 
surveyed, measurements made, staked off accurately on the 
surface, and afterwards carefully platted by scale on a map, 
of which that portion of the accompanying map describing 
this basin, is the reduced representation. 
The great reduction has to some small extent lessened 
the accuracy. The South and North Railroad or Helena Ver- 
tical Section, and the Helena Horizontal Section “I” to “J,” 
on the accompanying map, will show the relative position 
of the seams. By referring to the horizontal section, the 
Helena basin is shown on the right hand side and occupies 
that portion of the section between the boundary fault ver- 
tical coal measures and the interior fault vertical coal 
measures. The basin on the left hand side is the Cahaba 
basin, which will be described in the next chapter. The 
boundary fault on the southeast side of this basin, is an up- 
throw of ten thousand feet, while the interior fault near the 
South and North Alabama Railroad has an upthrow of only 
seven hundred feet, though in the southern part of the coal 
field this interior fault becomes an upthrow of fifteen hun- 
dred feet. The Helena or South and North vertical section 
gives the seams of both the Cahaba basin and the Helena 
basin. The coal measures of this basin can be seen most 
conveniently and to the best advantage, along and near to 
the can and North Alabama Railroad, between the north. 
