GEOLOGICAL INVESTIGATIONS IN MINNESOTA. 693 



fix their position at that date. He makes the first mention of 

 the red pipestone, or catlinite, of the southwestern part of the 

 state. 



Following these early travels was a period of territorial 

 exploration, extending from 1783 to 1858. When the War of 

 the Revolution closed the area which now comprises the state of 

 Minnesota was divided between the French and the United 

 States. From 1783 till the expedition of Lieutenant Z. M. 

 Pike, of the United States army, which took place in 1805, the 

 Upper Mississippi region was left almost as it had been under 

 the British, whose fur-traders still overran the region and still 

 floated the British flag at their trading-posts or " forts." Dur- 

 ing this period, however, an indefatigable English geographer 

 crossed the northern part of the state and recorded his observa- 

 tions of latitude, depositing his notebooks with the North- 

 west Fur Company, by whom he was employed, These rec- 

 ords have remained unpublished until recently. 1 The work of 

 this geographer, whose name was David Thompson, resulted in 

 determining the fact that the northern source of the Missis- 

 sippi was not north of the Lake of the Woods, where it was 

 assumed to be by the treaty of 1783. He reached Turtle Lake, 

 the "Julian sources " of the Mississippi, according to Beltrami, 

 twenty-five years before that gentleman saw the lake, and 

 recorded the latitude of the Mississippi at Red Cedar (now Cass) 

 Lake. Lieutenant Z. M. Pike in 1805 measured and described 

 the Falls of St. Anthony. This description, as it is accompanied 

 by a map of the river and cataract, has served to fix the posi- 

 tion of the falls at that date. He also described briefly the 

 Falls of Pokegama. In 1871 Major S. H. Long again visited and 

 described the Falls of St. Anthony, giving some notes on the 

 nature of the rocks that cause them. In 1820, and aarain in 

 1832, Mr. H. R. Schoolcraft was in Minnesota in the employ of 

 the United States government. He was the first to give a geo- 



1 E. D. Neill. History of Minnesota, fourth edition, p. 866. Minneapolis, 

 1882. Mr. J. B. Tyrrell has more recently published these notes in the Proceed- 

 ings of the Canadian Institute, March (published October), 1888. 



