154 The Missouri River. — Broadhead. 
since the close of the Canadian period, but it has been more 
or less subjected to slight oscillations from that time to the 
Permian. It began to rise just after the Canadian. It was 
above the waters before the Trenton period. From the Cana- 
dian to the beginning of the Lower Carboniferous it was dry- 
land. It then became sufficiently depressed to receive lime- 
stone deposits near its outer margin during the early Subcar- 
boniferous, a few beds of later Chouteau, and early Burling- 
ton. This was the last period of submergence of any part of 
the Ozarks. It again was subjected to elevation before the 
era of the Keokuk, and was subjected to slight throes inciden- 
tal to the uplift, which did not cease until after the Coal Meas- 
ures were deposited, but this was continued through a long 
succession of time but ceased at the close of the Palsezoic, its 
latter stage contemporary with the Appalachian revolution. 
During the Glacial and succeeding Quaternary, the lower riv- 
er was filled with boulders, sands and pebbles, now found in 
its bed. That the Missouri as well as the Mississippi was 
dammed or gorged at many places seems evident from the silt- 
like deposits now so thickly strewn along the neighboring 
hills, and to which the term "Loess" has been applied. The 
drift abounds in north Missouri but is rarely found south of 
the Missouri, and I have recognized it only at about three 
localities 5 and 15 miles from the Missouri. In Illinois it is 
limited by the Ohio. From the southern limit it extends away 
north. The Loess is well recognized only near the Missouri 
and the Mississippi ; I speak of the lower Missouri. Its origin 
as well as that of the present silt along the Missouri is from 
the "Bad lands" of the upper river. 
For 400 miles below Ft. Bentou the Tertiary and Cretaceous 
are weathered into curious forms, and as far down as Judith 
river are numerous trap dikes causing rapids. For 600 miles 
on the upper river are occasional outcrops of lignite and most 
of that portion presents the well known "bad land" scenery. 
The rocks are often weathered into many curious forms and a 
common feature is many standing columns forming numerous 
monument-like groups similar to those in the "Garden of the 
Gods," Colorado. These are a very interesting feature of the 
scenery of the upper Missouri. 
To the Palaeozoic cliffs of the lower river are given names 
which have become historic, as "Tavern rock," "Big" and 
