12 Geological History of the Ozark Uplift — Broadhead. 
The effort nearly ceased after the Burlington era except at a 
few points where the succeeding Keokuk and subsequent Coal 
Measures are slightly disturbed; then all was quiet. 
This great plateau seems to have been uplifted by forces act¬ 
ing at different places upon a broad or flat surface forming a 
massive anticlinal, and breaking off into a monoclinal around 
the margin. 
The upthrust was quaquaversal. 
We do know that several axes like* unto anticlinals have 
passed out on the east and north and have thence been traced 
for some distance away. If they had worked together, they have 
acted as a massive geanticlinal. On the west we observe rocks 
dipping to the west but no evidence of any, re markable upthrust 
of the Lower Carboniferous, but there may have been more 
active energy. On the north there is evidence of upturnings 
in Howard, Saline, Cole, Callaway, Randolph, St. Charles, 
Lincoln, Pike, Knox and St. Louis. 
It thus seems that the uplifting began just before the close 
of the Lower Carboniferous period and continued until after its 
close, and there may have still lingered a slight force into the 
succeeding Upper Carboniferous. This was nearly contempo¬ 
raneous with the close of the Appalachian revolution. 
While this extensive area was being uplifted deposites were 
gradually forming east, north and west, first sandstones, then 
successions of clay beds; then Coal plant marshes, dry land 
with luxuriant trees, the bark of which went to form the coal. 
The sea would roll in and overwhelm the laid down mass; sea 
shells and crinoids were innumerable, soon to die and be broken 
and ground together; life after life and deposit after deposit. 
Thus were the Coal Measure limestones formed. Sands and 
clay beds would also accumulate and be slightly uplifted so as 
to form the soil to grow another forest to form coal. So the 
process would go on, and when complete it would be slightly 
elevated in north-west Missouri, and the sea-trough, a little 
west of Missouri, be prepared for the ensuing Permian. 
Along the Mississippi river, from St. Louis to Commerce, the 
lower exposed rocks are Trenton, Upper Silurian and Lower 
Carboniferous, with the First sandstone at one place. East- 
wardly, in Illinois, these are soon covered by the Coal Measures, 
while on the west, and only a few miles away, the surface rocks 
