292 GEOLOGICAL SURVEY OF THE TEREITOEIES. 



scarcely to be expected. The rortbeastern part of tbe State may be 

 characterized as the region of swamps aud bogs. A strip of some tif- 

 teen or twenty miles in width aronnd the western end of the lake — which 

 is required to reach the summit of the blufl" — and which is rapidly as- 

 cending and mostly rugged, as a matter of course is well di-ained ; 

 but as soon as we pass .beyond this limit we enter upon a succes ion of 

 bogs and swamps separated by low ridges a i'ew feet in heigbt, which 

 continue until we come near to the Mississippi, and are, in fact, repeated 

 for a short distance west of it at some points. These ridges, which 

 appear to be composed entirely of drift-material similar in character and 

 color to the underlying or neighboring rocks, seem to have a general 

 north and south or northeast and southwest direction. This parallel- 

 ism of even these small swells between the boggy flats is but a repeti- 

 tion on a small scale of a remarkable feature of this part of the North- 

 west to which I have already alluded in speaking of the course of the 

 rivers. Owen calls special attention to it iu his report on. the geology 

 of this region as follows, (chapter iv, p. 333 :) 



As wbat I conceive to have been great valleys in the rocky strata of large portions 

 of Wisconsin and Minnesota have been filled up, aud the country, in a great measure, 

 leveled by the accuumlation of immense deposits of drift, it is not possible to determine, 

 with anything like accuracy, the width of the original valleys, nor the exact lines of 

 the anticlinal axis separating them ; but the distances from one synclinal line to 

 another may be ascertained now, with as much precision as the linear surveys of that 

 region, together with the draughts of the principal streams in the unsurvoyed portions 

 of the Territory, by members of the geological corps, will permit. Thus, from the 

 valley of Chippewa River, at the mouth of Manidowish to that of the Upper Saint 

 Croix, iu a direct line and at right angles to the course of the valleys, is aboitt sixty 

 miles ; and from the valley of the Saint Croix to that in which the Mississippi flow^, 

 between the outlet of Sandy Lake and the mouth of Crow Wing River, in the same 

 direction across the strike of the valleys, is about sixty-two miles ; and from this por- 

 tion of the valley of the Mississippi to the next parallel valley — in which Leech Lake 

 is situated — is about fifty miles ; aud from the valley of Leech Lake to the next great 

 parallel valley northwest of it — the one in which Red Lake lies — is about sixtj'-eight 

 miles ; showing a remarkable degree of uniformity in the undulations of the crust of 

 the earth throughout a very extensive region of country. * * Thei'e are 



three great systems of valleys iu the Northwest, besides numerous subordinate ones, 

 the valleys of each system preserviug a very uniform degree of parallelism with one 

 another aud with the smaller valleys between the anticlinal axes. 



He then proceeds to enumerate the varicms valleys of these systems 

 by the names of the rivers occupying them, showing this parallelism to 

 prevail to such an extent, not only in regard to the larger valleys and 

 streams, but even in respect to the numerous smaller water-courses and 

 valleys, as to make it evident that it arises from some law connected 

 with the geological forces aud structure. He gives it as his opinion 

 that the great structural features of the country are due to subterranean 

 movements, acting at dilferent periods on an immense extent of the 

 cmst of the earth and with great uniformity during each epoch, and not 

 to lo(;al disturbances only or to mere alterations of the surface from 

 glacial or diluvial action, however much these agencies may have 

 altered the face of the country. 



This may be, and doubtless is, true in regard to the direction of the 

 larger divides and valleys, but it will scarcely apply to the small ridges 

 which separate the bogs and swamps of Northeastern Minnesota or the 

 smaller parallel ridges of Dakota and Nebraska. Water alone, or water 

 and wind were certainly the forces that formed these ; i)erhaps glacial 

 action maj^ have i)layed a part in originally outlining them. 



Leaving the northeastern part of the State and moving westward 

 across the Mississippi toward the opposite boundary of the basin, we 

 observe a very marked aud important change iu regard to the surface- 



