192 Transactions of the Academy of Science of St. Louis 
a road cut about half way between Wanda and Oak Grove 
School in Madison County, Illinois. An irregular slab of red 
limestone, about 15 inches across and 4 inches thick, contain- 
ing a considerable quantity of dark-colored chert, was discover- 
ed a short distance north of Oak Grove School in a road cut. 
Piasa Creek valley in Jersey County, Illinois, exhibits two 
terraces, the upper of which can be recognized as part of the 
Cuivre Terrace. Small patches of sand caught in low notches 
in the bluffs a short distance from Elsah, Jersey County, Illinois, 
can be similarly correlated. 
In the northern part of St. Louis County there is a small 
tributary which empties into the Mississippi, half way between 
Fort Bellefountaine and Halls Ferry. This tributary has eroded 
several steep banks which show the same thick strata of alter- 
nating sand and clayey silt. In addition to the usual succession 
here, at the very top of the terrace there is about six feet of 
very thinly laminated silt, each layer less than an inch in thick- 
ness, the partings between the laminae showing paper-thin lay- 
ers of brown ferruginous material (Fig. 10). ‘The laminae 
strongly suggest seasonal accumulations. They have also been 
found beyond the area under consideration. 
Cuivre Terrace cannot be traced in any tributary of the 
Mississippi on either side of the river south of the mouth of 
the Missouri River. It appears to stop abruptly and can- 
not be correlated satisfactorily with any terrace farther south. 
This terrace may be traced in the tributaries of the Missouri 
River from Femme Osage Creek in St. Charles County westward, 
certainly as far as Frene Creek, near Herman, Gasconade 
County, Missouri, which is as far west as the study has been 
carried. The relatively thick strata of the terrace is well seen 
along Labadie Creek just north of Labadie, Franklin County, 
Missouri (Fig 11). The sand layers are usually less common than 
the silt, and with the increase in quantity of the stratified loess- 
like silt, it is easy to see how early investigators were inclined 
