. Farm development; an introductory book in agriculture, including a discussion of soils, selecting & planning farms, subduing the fields, drainage, irrigation, roads, fences, together with introductory chapters concerning farm business, and the relations of general science to agriculture . ter I the present Red River of the North. B. su ^ ^ ,. in the Mississippi river in glacial times when it flowed gently l his into the well-flllert cliannel of the ilinnesota liver. X. tht limestone. Y, the of sandstone helow. tllOUOht bv SOmC to very roughly mark the date when the glacial dam wasmelt
. Farm development; an introductory book in agriculture, including a discussion of soils, selecting & planning farms, subduing the fields, drainage, irrigation, roads, fences, together with introductory chapters concerning farm business, and the relations of general science to agriculture . ter I the present Red River of the North. B. su ^ ^ ,. in the Mississippi river in glacial times when it flowed gently l his into the well-flllert cliannel of the ilinnesota liver. X. tht limestone. Y, the of sandstone helow. tllOUOht bv SOmC to very roughly mark the date when the glacial dam wasmelted low enough to allow the waters of the valley ofthe Red River of the North, then the Ancient LakeAgassiz. to flow northward into the Hudson Bay andno longer swell the l^anks of the ^Minnesota River, whichbegan to shrink to asmall stream in the bedof the old river. In 1871 it was foundthat the Falls of , beside whicha number of flour andsaw mills had beenerected, were in dan-ger of being under-mined and washed out. The water had brokenthrough crevices in the lime rock, which was thin,and was wearing away the soft sandstone this would have caused the falls to recedevery rapidly, and to become a mere rapids, destroy-ing the valuable water power, the United States. Figure 12. The Falls of St. Anthony wlien Usrecession had begun. A. water in the Min-nesota, after it had ceased to receive theglacial water. B, water in the Mississippi riverabove the falls. 0, water in the Mississippiriver below the falls. D. the Falls of St. An-thony when yet at a point near the confluenceof the two rivers. GEOLOGICAL lilSTOKV OF THL EARTH 49 government put in a solid wall of masonry and an apronto preserve the falls, not in their picturesque form, butso as to conserve the water power. (See E in Figure 13.)
Size: 2770px × 902px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectagriculture, bookyear
