64 THE VERMILION IRON-BEARING DISTRICT, 



GEOI^OGICAL lilTERATURK. 



1825. 



BiGSBY, John J. Notes on the geography and geologj^ of Lake Superior: 

 Quarterly Journal of Science, Literature, and Arts, Vol. XVIII, 1825, pp. 1-34, 222- 

 269, with map. 



Bigsby, in 1825, describes the rocks at many points along the north 

 shore of Lake Superior. He also follows the old ronte from Lake Superior 

 to the Lake of the Woods for 430 miles, and obsei-ves an alternation of chlo- 

 ritic greenstone and amphibolitic granite. Near and on the Lake of the 

 Woods the greenstone passes into gneiss and mica-slate which is penetrated 

 by graphic granite. 



This statement concerning Bigsbj^'s observations is obtained from Bul- 

 letin U. S.. Geological Siu-vey No. 86, p. 51. The article to which these 

 statements were credited not having been found, they can not be verified; 

 and whether any further observations were made by Bigsby in the area 

 included in the Vermilion district has not been learned. 



Houghton, Douglass. [Fourth] Annual Report of the State Geologist, 1841. 

 State of Michigan, House of Representatives, No. 27. Reprint in "Memoirs of 

 Douglass Houghton, First State Geologist of Michigan," by Alvan Bradish, Detroit, 

 1889; 302 pages. 



In this report Dr. Houghton refers incidentally to that portion of 

 Minnesota which extends along the international boundary, a part of which 

 is included in this monograph, in the following words: 



The hills rise in broad and somewhat knobby steppes or plateaus, to heights 

 varying from 400 to 1,200 feet above the lake, and the summits of these hills are 

 usually not farther inland than from 10 to 20 miles. The rocks of the hills are very 

 frequently bare over considerable areas, and the valleys containing arable soil are 

 few and very narrow. 



The route of the fur trade to the northwest, via Rainy lakes, Lake of the Woods, 

 and Lake Winnepic, was formerly wholly carried on by passing over these hills 

 from a point a few miles west from the mouth of Pigeon River. The trail or 

 portage path passes over a low portion of the range, and finall}^ falls upon Pigeon 

 River, which is ascended to its source, from which, bj"- a series of portages, the 

 sources of the streams flowing northwesterl}^ are reached. The hilly portion of the 

 country, though of exceeding interest in a geological point of view, is the most 

 desolate that could be conceived. 



