CAHABA COAL FIELD: HENRYELLEN BASIN. 33 
was not visible to me from the rising to the setting of the 
sun, when the only guide to my location was the forms of 
the creeks and branches, or my apparent distance from 
some distant mountain of known location, it will easily be 
understood that absolute accuracy of location of outcrops 
was impossible without costly instrumental surveys. Even 
in thickly settled regions it is often impossible to get a sec- 
tion corner pointed out, since even at best, only a small 
percentage of the inhabitants have any knowledge o: these 
land marks, and where the ownerships have remained for 
a long time unchanged, these corners are frequently lost 
sight of entirely. For these reasons the section corners 
have not been often referred to. 
In the Henryellen vertical section on the map, the seams 
shown are those that I saw or dug to and found; the three 
horizontal sections above mentioned on said map, showing 
the Coal measures at three different points, and stretching 
across the Henryellen basin, represent the seams of coal 
that I either actually saw, or identified by the characteris- 
tic rocks that are near to and associated with them. Some 
of them I dug to, without making a thorough test, to con- 
vince myself of their identity with the seams in the same 
relative position in other parts of the Cahaba Cval Field, 
and to note their peculiarities. I would then abandon the 
test without obtaining a full section of seam, in order to 
give more time to forming the general sections, and locating 
the seams, considering that this result would meet the de- 
mands of the people of Alabama better than a number of 
disconnected details. The extent of the work made it com- 
pulsory on me to shun details and economize time as well 
as expense, so as to obtain the most knowledge of the Ca- 
haba field with the least outlay. In many cases, however, 
I made very accurate locations of many of the seams shown 
on the accompanying map, by taking the transit and chain 
in the one hand, and pick and shovel in the other, and 
making the one locate what the other brought to light, 
thus giving me a base line on which to locate the others by 
reconnoitering and computation of their relative distances. 
This shunning of the details required an effort on my part, 
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