GEOLOGICAL SURVEY OF THE TERRITORIES. 289 



is constructed along the lowest levels ; therefore our figures in the tables, 

 as a rule, represent the lowest points of the surface, and give us but 

 little idea of the local and isolated irregularities iu the contour; and 

 especially is this the case where the line crosses a divide between 

 different water-basins. In this case we should probably add 150 or L'OO 

 to the figures given in the table to get a true average of the elevation 

 of this divide, which is here called Leaf Eiver Hills, and which extends 

 some distance north and south. 



If we move uorth from the point where we cross the Mississippi, fol- 

 lowing up its valley, we observe that the ascent is rather more rapid thau 

 toward the west, as will be seen by the following list of elevations takeu 

 from General Humphreys' report on the Mississippi liiver: 



Above the 

 sea-luvcl. 



Month of Sandy Lake River 



Mouth of Swau River 



Head Falls of Peckagama 



Mouth of Leech Lake River 



Entrance to Lake Cass t. 



Entrance to Lake Traverse 



Itasca Lake 



Utmost sources of the Mississippi 



Fed. 



1,290 



1, 310 



l,;-!58 



1,402 



1,-156, 



1,575 



l.OisO 



As a matter of course, before we pass the divide in this direction a still 

 higher point will be reached, although there is no marked ridge sepa- 

 rating this basin from that north of it. 



If we pass westward to Ked River we find the elevation, where the 

 road crosses it, but *J00 feet abo^"e the level of the sea ; and as we mova 

 northward along its course it gradually descends, until, at Pembina, the 

 altitude, according to the railroad-surveys, is but 71)2 feet above the sea- 

 It is therefore evident that in passing from the basin of the Upper Mis- 

 sissippi into Eed Eiver Valley we have descended to a general level 

 about 400 feet lower, and in doing this have passed over a broad rim 

 from 100 to oOO feet higher than the upper plateau. 



What the vertical topography is northeast from the sources of the 

 Mississippi, I am unable to say ; but, as the waters of that section tiow 

 northward and eastward into another basin, it is evident the descent is 

 iu that direction, and the list of heights along Nameukan and Eainy 

 Lake Eivers, from Lake Superior to the Lake of the Woods, as given in 

 part below from the geological report of Mr. Hind, will show at least the 

 amount of this descent to that line or water-level. As a matter of course, 

 there is some kind of a divide between these two basins, but those who 

 have passed over it at different points say that as a general thing it is 

 an imi)erceptible swell ; in some places it is marked by low ridges, whick 

 separate the numerous marshes of this portion of Minnesota. The prom- 

 inent ridge maiked in some maps as running eastward fr©m the south- 

 ern margin of Eed Lake is wholly imaginary. 



The following list of elevations along the Nameukan and Eainy Lake 

 Eivers, taken from the geological report of Mr. Hind, gives us the slope 

 of the main channel of this ncnthern international basin, and is very im- 

 portant iu this connection, although part of the link between it and the 

 Mississippi Basin is wanting : 



10 G s 



