Meg atony x -beds in Kansas. — Udden. 
341 
B 
WHS 
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long extending north and south from the city 
of Salina to about fifteen miles south of Mc- 
Pherson. The superficial material in the bot- 
tom of this depression is composed of the de- 
posits in question, while the borders expose 
the underlying country rock, the so-called 
"Red-Beds" and the Dakota sandstone. It 
suggests an old valley partly filled with sedi- 
ments and now again under excavation. The 
Smoky Hill river has carved its bed through 
the northern end, and here erosion has nearly 
reached the old bottom, and the river has 
thrown its mantle of alluvium over extensive 
areas along its course. The southern end, 
extending from the valley of the Smoky to 
that of the Little Arkansas, is marked by a 
rather steep slope along the western margin 
and by a chain of lakes and basins, that make 
a rather unique feature in a country otherwise 
well drained. This end is crossed at right 
angles by the water-shed between the two prin- 
cipal drainage sj'stems of the state, the Kan- 
sas and the Arkansas. As might be expected, 
the deposits here attain their greatest thick- 
ness, which cannot be far from 150 feet. It 
is at a point where a line of minimum ero- 
sion, the watershed, intersects a line of max- 
imum development, the trough. 
Taken in ascending order, the materials de- 
posited in the southern end of the trough are 
as follows : ( 1 ) gravel, ( 2 ) sand, ( 3 ) clay, 
( 4 ) volcanic dust, ( 5 ) yellow marl. The thick- 
*5 £~ ness of each of these, as well as their composi- 
H^J tion, even that of the cla\', is very variable. 
clip The gravel is mostly confined to the deeper 
-eg S.| parts of the trough.' It is mostly strongly 
cross-bedded and it varies considerably in 
coarseness. In a few places carbonate of lime 
is present as an efficient cement. Pebbles of 
different kinds of crystalline rocks are not un- 
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