Archaeological Investigations in Jefferson County, Mo. 153 
Pennsylvanian or more recent rocks are not present but the 
Quaternary is represented by largely unconsolidated lacustrine 
deposits in terraces along the tributary streams. These terraces 
appear to have been formed by impounding when the glaciers 
ammed the water gaps or by checking of the Mississippi River 
depositing overloads of glacial debris. Some large igneous rocks 
and quartzites were possibly rafted into the area by ice. 
Much of the Quaternary deposits contain fossiliferous de- 
Posits of mammalian bones. These have been picked up and 
dug out of bluish clay and gravel of ancient lake beds by stream 
action, uneroded remnants of which are found as residual pockets 
in various parts of the country. Usually they lie beneath heavy 
recent overburdens. Occasionally they are found in secondary 
Position along present stream beds.? 
PREVIOUS INVESTIGATIONS 
Mardly an aboriginal mound has been untouched by exca- 
"ators, and the plow has destroyed many of the superficial vil- 
lage deposits, 
There have been a few temporary visits to the county by 
archaeologists in the past most of whom excavated small test 
‘Trenches in mounds and graves. Chief among these have been 
David I, Bushnell, Jr., and Gerard Fowke both working for 
Smithsonian, 
_ The results of Mr. Bushnell’s investigations and conclusions 
for Jefferson County have been reported in the Proceedings of 
the U nited States National Museum. 
Mr. Fowke’s investigations were carried on partly at ~ 
‘ame location as those of Mr. Bushnell,3 and partly along hig 
eT b 
'The section on geology was written from notes assembled by 
Mr. Clarence Jenni. . 
“Archaeological Investigations in Ste. Genevieve County, Missouri, 
Vol. 46, pp. 642 and 655. , 
‘ ee . : i i,” Bureau o 
*“Mound and Salt Springs at Kimmswick, Missouri, 
American Ethnology Annual Report No. 44, pp. 487 - 488. 
