subsurface geology and coal resources of the pennsylvanian system ...

Total depth: The total depth of the hole is given to the nearest
foot.
Quadrangle number: This refers to the number of the quadrangle
as given on the Index Map (page 52) in the "List of Publications
on the Geology, Mineral Resources and Mineral Industries of
Illinois, * * January, 1950.
An asterisk (*) after the quadrangle number indicates that
the datum point is not shown on the structural contour map drawn
on the No. 6 coal.
Year drilled: Only the last two figures of the year drilled dre
shown; as "25" means "1925."
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Doubtful information: A notation here indicates that, although
information is available, the accuracy of some part of the data
is in doubt. The nature of the doubt is shown by number, as
follows :
2. Correlation of key coal bed 6. Correlation and elevation
3. Exact location 7. Location and elevation
4. Surface altitude 8. Depth to key coal bed
5. Correlation and location
Datum beds: The names of the beds shown in columns for datum
beds are indicated by line at the top of each column.
SC = Shoal Creek limestone
WF = West Franklin limestone
No. 7 ="No 7" coal bed
No. 6 = Herrin "No. 6" coal bed
No. 5 = No. 5 coal bed
No. 4 = "No. 4" coal bed
Palzo = Palzo sandstone
Base Penn = Base of the Pennsylvanian system
Little Menard = Little Menard limestone
GD = Glen Dean limestone
Depths'to datum beds are given to the nearest foot to either
the top or bottom of the bed, as indicated in the text. Elevation
of the datum bed is in feet above sea-level. An asterisk (*) following
this figure indicates the elevation is below sea-level.
Thickness is given in feet and inches. *O indicates that the coal
bed is eroded or is absent at its horizon for some other reason.
Where no coal data are given the information is unreliable or
the hole did not reach the coal bed. Where elevation is shown
but not depth, the former is estimated from other data.