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IOWA ACADEMY OF SCIENCE Vol. XXIV, 1917 
measured in dollars and cents. The process required the same 
nicety of calculation, but with more variable factors, as when 
Leverrier figured out for the first time the position in the heav- 
ens of the then unknown planet Neptune. 
In the region under consideration the general slope of the 
upland plains surface is v eastward or southward ; the general 
slant of the strata is to the westward. In other words the 
present peneplain bevels all the rock-layers between the Missis- 
sippi and Missouri rivers. It so happens that the coal seams 
of the region, in Appanoose and Wayne counties, in Iowa, and 
in Putnam, Mercer, Sullivan and Adair counties, Missouri, pre- 
sent greater individuality and cover wider areas than do the 
majority of the coal beds of the two states mentioned. With 
them also are associated several distinctive limestones which 
serve as guide-horizons. 
The especial difficulty in attempting to decipher the detailed 
stratigraphy of this district is that it is deeply covered by 
glacial till, making outcrops of the Coal Measures few and far 
between. Upon first reentering the field it was inferred that 
the existence of the long tongue of Bethany limestone was due 
to the fact that it lay in a trough. This soon proved to be the 
case. The noteworthy feature about the trough was that it 
was plainly asymmetrical. To the northeast all the coal beds 
were found to rise steeply. There was apparently present a 
sharp monoclinal fold having its lower limb to the west. On 
the section between Princeton, Missouri, and Seymour, Iowa, 
there was an abrupt descent just out of Powersville of nearly 
200 feet. On the line between Milan and Centerville there 
was, five or six miles southwest of Unionville, a similar abrupt 
descent. Between Milan and Kirksville like- conditions and fig- 
ures obtained. 
In previous years it had been found that farther south or 
southeastward, near Macon, there existed what appeared to be 
a marked anticline, or perhaps monocline, in which the rock 
layers on one side sloped steeply to the northeast. Still farther 
to the southeast it had been noted that the coal-bearing strata 
were abruptly cut off from the Early Carbonic and other lime- 
stones along a rather sharply defined line running through 
Shelby, Monroe and Ralls counties. This phenomenon had 
never been satisfactorily explained. 
