OF THE NORTHWESTERN STATES. 9 



oxide of iron, with alumina enough to cause adhesion. In the valley of Rainy 

 lake river and its tributaries, the color resembles that of ashes, but a little darker. 

 It is the same on the headwaters of the Mississippi, as low as the Crow Wing 

 river, and on the upper waters of the St. Louis river, which discharges itself into 

 Lake Superior at the west end. 



On the summit lands, where the streams flowing northerly into Hudson's bay, 

 southerly into the Gulf of Mexico, and easterly into Lake Superior, have their 

 rise, all the members of the drift formation are developed. No. 3 occupies the lower 

 levels, and becomes more conspicuous as we descend those streams from the height 

 of the adjacent land. 



The elevation of the summit region is not great, nor is the country broken. 

 Most of it is level and swampy, attaining a height of only 1500 to 1800 feet above 

 the ocean. It is well described by Nicollet as a region of rocks, swamps, and 

 water. The Mesabi Range, which is crossed, in passing from the St. .Louis to the 

 Vermilion river, a tributary of Rainy lake, is rather the termination of a rocky 

 plateau, than a regular chain of mountains. In descending the St. Louis river, the 

 ash-colored drift clay of the Embarras and Savannah rivers, assumes a more purple 

 hue, near the mouth of the Savannah. 



The purple graduates into red, betAveen this point and the Knife rapids, and 

 becomes entirely red on the Grand Portage. The red extends along the shores of 

 Lake Superior to St. Mary's, and to Lake Huron. It is found on all the tributaries 

 of Lake Superior which flow into it from the south up to their sources, and beyond 

 the summit on the streams that run southerly into Lake Michigan. 



Fig. 6. 



Beds of Mixed Dkift, Chestkut Street, Milwaukee, WiscoHsm. Memokakda. — 1. AUuvinm. 2. Well 90 feet in 

 Clay. AAA. Red clay and red hardpan. B. Yellow sandy clay. C. White and purple clay. E E. Gravel. D. 

 Mixed colors. F F F. Blue laminated clay, passing into purple hardpan. 



Fig. T. 



Dkift Blcffs, Shore of Lake Michigan, 5 miles South of Milwaukee ; view from the water. A. Yellow sand 

 and gravel. B B. Coarse gravel. C C C. Purple hardpan passing into red clay. 

 2 April, 1306. 



