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<br />FIGURE 3
<br />
<br />PHYSIOGRAPHIC DIVISIONS, PROVINCES,
<br />SECTIONS, AND SUBSECTIONS
<br />
<br />
<br />1"'-
<br />- I -"
<br />, MISSOURI Pl.A,T:AU, -~
<br />~-~-~~--<, r~~~_~I_~T~~_~~__l;, - :----'!l/ --'\
<br />
<br />/ --- ~~", """, . -.\
<br />': "" - ' - \
<br />'- \ -, \.
<br />GREAT '-','-'
<br />" - - - - - -- "----
<br />MISSOURI,PLATEAU, \
<br />UNGLACIATED -, ':\
<br />
<br />\;}r. ' N Tf R , 0 \: . ..~
<br />
<br />
<br />- . __ _ ' BLACK ,)__:
<br />- " -HILLS \ '';-~ ~
<br />~- -_ \ I
<br />~ '. C Ell T R Al s::
<br />/......................-./.(., -, ':'\
<br />f '~_ (______\,
<br />~j SAND HillS ._'::~,; \ 1
<br />" -' \ -- - "
<br />~.V\ (;' .,' __ \ ~
<br />'. ',:-; -.-,...... '\ . \ \...<'~
<br />/ ~UTH CE~TRAL \ " _
<br />HIGH PLAINS / LOESS HILLS \ lOW l II II O_S
<br />( \ . ,
<br />~'P~l~II~------ ,,->. -
<br /><-'Y _ __ '_~"!K",A) INS "- ,-' ,/',
<br />
<br />C"_, CENTRAL KANSAS /. -, 04 '\
<br />"< ~o.~LING PLAINS -
<br />~l?' "
<br />
<br />"...---~
<br />
<br />\\- ...
<br />\,
<br />
<br />g/
<br />
<br />SOUTHERN ':::------ ,_
<br />ROCKY MTS. -
<br />
<br />~
<br />
<br />'-~f -
<br />[
<br />
<br />BOUNDARY LEGEND
<br />
<br />- PHYSIOGRAPHIC
<br />- PHYSIOGRAPHIC PROVINCES
<br />- PHYSIOGRAPHIC SECTION
<br />---'-- PHYSIOGRAPHIC SUBSECTION
<br />
<br />DASHED LINES REPRESENT BOUNDARIES POORLY KNOWN.
<br />HIGHLY GENERALIZED OR NOT CLEARLY DEFINED
<br />
<br />developed by erosion of dome-type uplifts. Principal
<br />among them are the Black Hills in western South Dakota
<br />and northwestern Wyoming, an elliptical-shaped area 60
<br />miles wide and 125 miles long. That portion of the
<br />Great Plains north and east of the Missouri River, and at
<br />places extending south of the river, has been influenced
<br />by the continental glaciation. Here, the topography was
<br />shaped mainly by erosion of the glacial drift and till.
<br />The Central Lowlands province of the Interior Plains
<br />Division, bordering the Great Plains to the east, often
<br />does not have a perceptible line of demarcation.
<br />Roughly, the 88,000-square-mile area extends from a
<br />line between Jamestown, N. Dak., and Salina, Kans., to
<br />the Mississippi drainage divide. This entire area has been
<br />developed by erosion of a mantle of glacial drift and till.
<br />The northern portion is composed of the coarser drift
<br />material and the southern portion, the finer till.
<br />
<br />8
<br />
<br />~\~
<br />
<br />~
<br />
<br />"
<br />
<br />t
<br />
<br />SC':'L[ I /tI.~ooooo
<br />o '0.0
<br />
<br />.aPP~OJ('MATE SCALE IN MILES
<br />
<br />
<br />~
<br />
<br />~\
<br />
<br />In the southeast portion of the basin, in Missouri, are
<br />the Ozark Plateaus, a province of the Interior highlands
<br />Division, containing about 11,000 square miles of
<br />drainage area. Its topography, developed by erosion of
<br />the ancient though moderate Ozark uplift, is hilly to
<br />mountainous. This moderate uplift and the underlying
<br />sedimentary formations in great depth leave only sedi-
<br />mentary rocks exposed. Limestones are the basic surface
<br />materials and gave rise to cavernous channels with spring
<br />flows which abound in the area.
<br />Because the basin is so vast and was influenced by a
<br />variable geologic historical development, many sectional
<br />variations exist, as shown on figure 4. This reflects eight
<br />major types of areas, considering soil types and the
<br />dominant topographic characteristics.
<br />Areas properly defined as "mountains" include the
<br />Rocky Mountains of Colorado, Wyoming, and Montana,
<br />
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