IOWA ACADEMY OF SCIENCES. 
197 
UPPER CARBONIFEROUS OF SOUTHWESTERN IOWA. 
BY E. H. LONSDALE. 
The district at hand is one somewhat remote from any known 
field of productive Coal Measures, but being Upper Carbonifer- 
ous in age is a region to which considerable geological and 
economical interest has been attached. There has always been 
an anticipation of finding heavy fuel veins, but as yet these 
looked-for strata have not been positively located. Reports, 
often manufactured, and the meeting of thinner veins of coal, 
have led to the increased expectations now prevalent in the 
district. 
Since the publication of the results of the reconnoissance by 
Meek and White in 1867 and the more extended report by the 
latter a few years afterwards all prospecting and hopes have 
been based upon the conclusions of these authors. Certain of 
these estimates have proven to be misleading. In the prelimi- 
nary reports* it was predicted that the Upper and the then- 
called Middle Coal Measures would be passed through at a level 
not exceeding 500 feet lower than the water of the Missouri 
river at Nebraska City, almost the extreme southwestern point 
in Iowa. Here the elevation above sea level is 907 feet and the 
drainage level of the greater portion of the southwestern dis- 
trict is from 50 to 200 feet lower. Consequently the depth in 
the valley to the Lower Coal Measures would in no case be 
more than 700 feet. This is upon the supposition that the 
Carboniferous strata in this region lie approximately level. 
But, considering the dip as southwestward and at the rate of 
ten feet per mile, as is usually accepted, then at the southwest 
corner of Adams county, about fifty miles from Nebraska City, 
the base of the “Middle” Coal Measures would rise to within 
about 200 feet of the surface. 
^U. S. G^l. Surv. of Ter., First Aan. Rep., p. 7. 1878. 
