524 STUART WELLER © 
doned quarry one-half mile farther down stream, a total distance of 
from two and one half to three miles, it is clearly seen that the Rich- 
mond rests upon higher and higher strata of the Kimmswick lime- 
stone. At the northern end of this section the uppermost bed of the 
Kimmswick, immediately beneath the Richmond, is characterized by 
a fauna in which bryozoans are the most conspicuous element. At 
Glen Park the upper bed of the Kimmswick is a higher stratum than 
that farther north, and the fauna contains more trilobites and _pele- 
cypods. Farther south a still higher bed of the Kimmswick lime- 
stone, characterized by many specimens of a large Receptaculites, is 
immediately subjacent to the Richmond. These stratigraphic con- 
ditions clearly indicate that in post-Kimmswick time the region was 
elevated above sea level, and the beds obliquely truncated before the 
deposition of the Richmond. The time hiatus represented by the 
unconformity in this region, as in Calhoun County, is doubtless the 
period during which the Utica and Lorraine formations were being 
deposited east of the Cincinnati arch. 
In Monroe County, Illinois, conditions identical with those in 
Jefferson County, Missouri, are shown in the quarry of the St. L. I. 
M. &S.R.R. at Valmeyer. Still farther south, at Cape Girardeau, 
Missouri, the same section is repeated in the same manner, although 
the details have not been so carefully studied as in the more northern 
localities. 
In the northern portion of the Mississippi Valley region, in eastern 
Iowa, northwestern Illinois, and Wisconsin, no stratigraphic break 
between the Galena limestone below, which is contemporaneous with 
the Kimmswick limestone, and the superjacent Maquoketa shales has 
been certainly established, but the faunal break is essentially iden- 
tical with that in Calhoun County where the physical break is clearly 
shown, and one is forced to the conclusion that the physical uncon- 
formity is really present, although obscured. 
Westward from the Mississippi River, across the great plains, the 
older rocks are completely buried beneath younger formations. In — 
the Big Horn Mountains in Wyoming, however, as has recently been 
shown by Darton,’ conditions are present which are comparable to 
t “Geology of the Big-Horn Mountains,” U.S. Geological Survey, P. R. No. 51, 
pp. 26-29; also Bull. Geol. Soc. Am., Vol. XVII, p. 547. 
