Problems, Middle Mississippi River Region, Pleistocene Time 237 
runs from Red Rock in Perry County, through Wittenberg, dis- 
appears below the Mississippi at about this place and this seems 
to be very close to the boundary between the two groups of 
terrace levels. Although the evidence is by no means conclusive, 
it is certainly an indication of post-Wisconsin movement, either 
along this fault or another one that might be concealed near 
it. It may be worth while to mention that Shepherd’ wrote 
in connection with he New Madrid earthquake: 
“. . . the primal cause of the New Madrid earthquake 
may have been due to readjustments of fault lines in 
the Ozarks.” 
By this it is not intimated that the New Madrid earthquake 
was occasioned by movement along the fault between Red Rock 
and Wittenberg. Rather it is intended to point out that there 
are reasons to believe that there have been recent movements 
on some of the faults in the Ozarks and that the displacement 
of the Festus Terrace by movement along a fault in post- 
Wisconsin time is an entirely reasonable assumption. 
PLEISTOCENE History SUMMARY 
1. Grandian epoch: the Nebraskan ice reached a point about 
25 miles north of the confluence of the Illinois, Mississippi, and 
Missouri Rivers, Further ideas regarding the Nebraskan in this 
region are at present conjectural. 
2. Ottumwan epoch: the Kansan ice from the Kewatin cen- 
ter made extensive deposits of drift in Lincoln County, Missouri. 
This ice sheet blocked the stream that at that time occupied 
the present valley of the Mississippi. It also blocked the Missouri 
River in the general vicinity of Vigus in St. Louis County, there- 
by producing the Boeuf Terrace up the Missouri River. The 
ice probably extended into St. Louis and even turned north- 
eastward to Alton. If this was so, the Mississippi Kiver, at 
that time occupying the present course of the Illinois River, 
must also have been blockaded. Kansan ice, from the Labrador 
