Forest physiography; physiography of the United States and principles of soils in relation to forestry . LAURENTIAN PLATEAU AND ITS OUTLIERS 577 SOUTHERN DISTRICT The southern portion of the SuperiorHighlands (central-northern Wisconsin) con-sists of a main upland, an uplifted and dis-sected peneplain with a very even summitbelow which the Wisconsin River and itstributaries have eroded their valleys andabove which project a few isolated hills andridges. The plain gradually descends south-ward and finally diverges; one plane runsunder the Potsdam sandstone which formsthe northward margin of the
Forest physiography; physiography of the United States and principles of soils in relation to forestry . LAURENTIAN PLATEAU AND ITS OUTLIERS 577 SOUTHERN DISTRICT The southern portion of the SuperiorHighlands (central-northern Wisconsin) con-sists of a main upland, an uplifted and dis-sected peneplain with a very even summitbelow which the Wisconsin River and itstributaries have eroded their valleys andabove which project a few isolated hills andridges. The plain gradually descends south-ward and finally diverges; one plane runsunder the Potsdam sandstone which formsthe northward margin of the Paleozoic de-posits of the region and another extendsacross the Paleozoic formations. In thevicinity of Grand Rapids, Wisconsin, andapproximately at the border of the sand-stone district, looo feet above the sea, thevalley bottom of the Wisconsin River prac-tically coincides with the level of the loweror pre-Cambrian plain. The pre-Cambrianand the main crystalline rocks are verymuch folded and crumpled and the dips areat various angles and frequently almost ver-tical, Fig. 233.^ The structures are
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectforestsandforestry
