276 ASSINNIBOINE AND SASKATCHEWAN EXPEDITION. 



altitude and breadth at the Height of Land. A similar 

 disposition obtains at Milles Lacs on the western slope, 

 where the elongated dome-shaped intrusions are about 100 

 feet high and flanked with schists. 



On the Pigeon Eiver route the granite and syenite 

 ranges acquire more imposing altitudes, sometimes attain- 

 ing an elevation of nearly 1300 feet above Lake Superior, 

 but the axis of each range preserves a general N.E. and 

 S.W. direction parallel to the coast of the lake. This 

 uniform disposition is maintained as far as Basswood 

 Lake on the southern route. 



The mountain range constituting the Height of Land 

 dies out in a great measure after crossing the St. Louis 

 Eiver in its course south-west ; but granitic, metamorphic, 

 and trap rocks are met with at various points along the line 

 of bearing as far as the Mississippi, and reappear again 

 on the Minnesota river.* 



At Snake Falls, on the northern route, the river passes 

 over a schist highly inclined to the N.E., and below them, 

 many fine exposures of the same schist occur on islands, 

 frequently projecting like the end of boards of unequal 

 lengths leaning against one another, and varying in thick- 

 ness from two to five inches. Three miles below Snake 

 Falls, the rock passes into gneiss, and numerous veins and 

 dykes of granite are seen to penetrate it nearly at right 

 angles to the strike ; the dip is here N.W. Ten miles 

 below Snake Falls, mica schist again comes into view, 

 intersected with quartz and felspar bands from one to two 

 inches thick. The strike is E. 5° N., and the dip nearly 

 vertical. At the Gfrand FaUs of the Nameaukan, the 

 schists are tilted by steps in the form of the segment of a 

 circle. In Lac Nameaukan, dome-shaped granitic islands 

 parallel to one another, and of oval form, present them- 



* Dr. Norwood. 



