336 SYSTEMS OF VALLEYS 
only rise to the height of between twelve and thirteen hundred feet above the Lake, 
at the highest points in our territory, and less than two thousand feet above tide- 
water. The valleys between these mountain-ridges are often from five to six 
hundred feet below the summits, and vary in width from one or two miles to 
narrow gorges not over two or three hundred yards across. 
The scenery of the whole extent of the ranges north of the Lake, is bold and pic- 
turesque. The outline of the chains of hills and ridges is very irregular, and charac- 
teristic of the rocks which compose them. Some of the hills are round-backed, some 
of them angular, and others jagged, with an occasional peak here and there, but no 
spires. In the trap region, rugged mountain scenery prevails; in the schistose and 
granitic belt, occasional knolls or low ridges, with intervening lakes or swamps, make 
up the scene; and in the drift region, lines of conical hills, irregular depressions, 
and low ridges with long slopes, constitute the main features of the country. The 
rivers have numerous falls and cascades, and, in the small, deep valleys, often 
expand into beautiful lakes, the clear waters of which appear almost black, under 
the dark shadows of the high rocky walls which enclose them. 
The lines of eruption are various, and the materials thrown out differ greatly ; but 
they agree in the various parallel lines to a very near degree. There are five 
principal axes of elevation, due to eruptions: east 45° north; north 45° west; 
north and south; east and west; and north 30° east. The first three of these, as 
already stated, stamp their impress on the general features of a large district of 
country. The first of the other two principal axes is best developed between 
Pigeon Point and the mouth of Kamanosisatikag River, and the second between 
Fond du Lac Supérieure and Two Island River; but they are discoverable at various 
other points, as far south as the Falls of the St. Croix, and as far north as the 
dividing ridge between the waters of the Mississippi and Hudson’s Bay. As a 
rule, almost without exception, the narrow dikes which run parallel with the 
principal axes are composed of materials similar to those of the heavy ridges and 
dikes having the same direction. 
The direction of the shores of the western portion of Lake Superior, and the 
width and configuration of all that portion lying between a line drawn north- 
westerly from the Apostle Islands to the mouth of Two Island River and Fond du 
Lac Supérieure, shows the correspondence of the basin of that part of the Lake with 
the valleys of the large streams south and southwest of it. 
The range of greenstone ridges which begin at the Great Bend of St. Louis 
River, and run northeasterly (north 30° east), form a true anticlinal axis,—the 
line of elevation crossing the boundary line between the sources of Arrow River 
and Mountain Lake. And, although this range, and the north-45°-east one, which 
begins near the same point, impress the features of the country northwest of the 
Lake most prominently (modified in the easterly portion by the heavy east and west 
dikes), still, the structure of the whole region is greatly complicated by the numerous 
narrow dikes which traverse it in other directions. 
In consequence of the greater facility with which granitic rocks decompose, the 
hills and ridges along the northern water-shed are lower, in relation to the valleys 
