STRATIGRAPHICAL GEOLOGY 
341 
and described. Working under the impression that it was the 
same bed which further north had been widely observed to rest 
directly upon the St. Louis limestone but locally separating the 
latter from the Coal Measures, Swallow,^ Shumard,^ and others 
of their day, termed this terrane the Ferruginous sandstone. Main¬ 
ly because of this fact it was that the stratum so long escaped 
understanding and proper christening. 
Particular interest in the Aux Vases sandstone rests at this 
time in the leading role which it played in the primitive differen¬ 
tiation of the Early Carbonic section of the Continental Interior. 
General oversight of this fact by later workers appears to lie at 
the bottom of most, if not all, of the subsequent and wide-spread 
confusion and erroneous interpretation of the real stratigraphic 
significance of the formation. When the Paleozoic sequence of 
the Mississippi Valley was first being resolved, something less than 
three-quarters of a century ago, this sandstone, which we now 
designate as the Aux Vases, was the theme of one of the most 
acrimonious controversies of that day. 
The original Ferruginous sandstone, or basal member of the 
Coal Measures, with which the Aux Vases sandstone was for a 
long time confused, was in the beginning, commonly classed with 
the St. Louis limestone, rather than with the immediately over- 
lying Coal Measures. The later known Kaskaskia formation of 
southern Illinois and western Kentucky was, because of its char¬ 
acteristic Archimedes fossils, thought to hold a stratigraphic posi¬ 
tion beneath the limestone of St. Louis. Thus, the Kaskaskian 
Archimedes-bearing beds were readily paralleled with the Archi¬ 
medes limestone of Keokuk and Warsaw, and other northern lo¬ 
calities. It was not until many years afterwards that it was dis¬ 
covered that there really existed three distinct Archimedes lime¬ 
stones instead of one. Interpretation of the fossils was clearly at 
fault. 
At this distant day it is not known definitely just when first 
suspicions were aroused that all of the Subcarboniferous section 
had not been actually recognized. The attendant circumstances 
can only be surmissed. It is probable that first inklings concern- 
2 Missouri Geol. Surv., 1st and 2nd Ann. Repts., p. 91, 1855. 
3 Ibid., pt. ii, p. 181. 
