019

• Format: Text
• Language: unknown
• Published: State Historical Society of North Dakota
• Subjects: Bad Lands; Ice Sheet
• Online Access: http://cdm16921.contentdm.oclc.org/cdm/ref/collection/ndsl-books/id/55469

13 GEOLOGY OF THE HILL COUNTRY Having now in very brief outline presented some'of the principal facts concerning the Quaternary or Pleistocene Age with its glacial epochs, it will next be in order to speak of the driftsheet of the hill country, for it manifestly has but one and that only a meager representation of the drift of the Wisconsin epoch. In the first place let us endeavor to picture the eastern front of the high land where it bordered on the upper depression of the Red River Valley, and as it existed just before the first Ice epoch. The first cycle of erosion had reduced the upland country generally to a peneplain condition, that is, while the surface presented many inequalities of moderately high and low ground, the country in a broad sense constituted a plain slightly inclined toward the west. But erosion had sculptured the eastern verge of the peneplain for one, two, or more miles back from its edge, into "Bad Lands" forms, yet on a smaller topographical scale. (The Bad Lands were never overridden by any ice-sheet and have ptettivtd their preglacial aspect, except as modified somewhat by continued erosive agencies.) The tendency would have been the production of flat-topped table-lands with steep sides, and the occasional lowering of areas into shallow valley-like forms along drainage lines that headed many miles back from the verge of the Red River Valley,: and narrow steep-sided gorges for the shorter drainage lines. While Moraine and other hill townships in the western, part of the county have in some measure preserved the broader outlines of preglacial sculpturing, minor features were nevertheless radically changed by the grinding agencies of successive, ice-sheets which toned down the rough forms of land sculpture to more gently flowing outlines. The most of this smoothing down process was effected in the Albertan-Kansan stage, which as far north as the Red River Valley probably formed one continuous glacial epoch, although in the Kansan stage the ice sheet did not extend as far to the west as in the first stage. Whether the hill country Scanned with a Zeutschel Zeta book scanner at 300 dpi. Edited in Multi-page TIFF Editor.