IOWA ACADEMY OP SCIENCES. 
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basin. For this reason there is considerable difficulty in 
explaining this unusual occurrence, unless it can be accounted 
for by replacements or by conceding the portion just above the 
sandstones to be barren Lower Coal Measures. 
At Red Oak only shales and limestones are recorded in a 650 
foot well section — all certainly Upper Coal Measures; while 
thirty miles northeast, at Atlantic, a well was bored 1,300 feet 
deep and down to the last 250 feet the strata passed through 
consisted for the greater part of similar materials, and from 
1,100 to the bottom the same sandstones which were met at 
Glenwood were discovered. Allowing for the dip and respec- 
tive elevations of the two points the discrepancy in the depths 
to sandstone would just about be explained, the total dip being 
from about 300 feet between the two points. 
At Clarinda, about fifty miles south of Atlantic, a prospect 
hole 1,020 feet deep was put down, and from the record it would 
seem conclusive that the Upper Coal Measures were not fully 
penetrated. The same may be said of the holes at Shenandoah 
and Riverton to the westward. The records of shallower bor- 
ings in southwestern Iowa might be gone over, and likewise the 
drillings at Plattsmouth, Omaha and Council Bluffs, but these 
data simply corroborate the statements already made and 
nothing at variance is found. 
Considering, therefore, the data at hand as at least in a man- 
ner reliable, the following conclusions pertaining to the Upper 
Paleozoic rocks of southwestern Iowa might be given: 1. The 
combined thickness of the divisions of the Upper Carboniferous 
approximates 2,000 feet. 2. The Upper Coal Measures, or 
Missouri series of Keyes, has a thickness of from 1,400 to 1,500 
feet. 
In support of this it may be stated that Broadhead* found 
the Upper Coal Measures in Atchison, the most northwestern 
county in Missouri, to be more than 1,100 feet thick, and the 
Upper Carboniferous as 1,900 feet. Later information has led 
this author to place the thickness of the latter in Missouri as 
1,979, and the old Middle and Lower as 664 feet. These figures 
relating to the superior division have been more recently 
vouched for by Winslow f. 
After a brief reconnoissance of the Iowa- Missouri coal field, 
and a review of the work of Meek, White and Broadhead, 
* Iron Ores and Coal Fields, Geol. Surv. Mo., pt. ii, pp. 6 and 98. 1873. 
t Mo. Geol. Sur., Prelim. Rep. on Coal. p. 33. 1891. 
