306 APPENDIX. 



in the rough coast between the Chocolate Eiver and Kewaiwenon, 

 cross the Mississippi at the Petite Roche, above the Falls of St. 

 Anthon}^, and put out spurs as low down as the source of the 

 Fox, the St. Croix, and the head of the St. Peter's Rivers. 



These glimpses of some of the leading points in the geological 

 structure of the regions visited, will enable you to follow my de- 

 tails more understandingly. These details begin at Detroit. From 

 this place the expedition passed, by water, along the southern 

 shores of Lakes St. Clair, Huron, and Superior, to the Fond du 

 Lac ; thence, up the River St. Louis, to the Savanne summit. 

 Thence we proceeded across the portage to Sandy Lake, which 

 has an outlet into the Mississippi, and followed up the latter, 

 through the lesser Lake Winnipek, to the entrance of the Turtle 

 River, in Cass, or upper Red Cedar Lake, which is laid down by 

 Pike in north latitude 47° 42' 40".* The state of the water was 

 unfavorable to going higher. 



From this point, wdiich formed the terminus of the expedition, 

 we descended the Mississippi, making portages around the Falls 

 of Pekagama and St. Anthony, to Prairie du Chien. An excur- 

 sion was made by me down the Mississippi to the mineral district 

 of Dubuque. We ascended the Wisconsin, to the portage into 

 the Fox River, and traced the latter down to its entrance into 

 Green Bay. At this point, the expedition separated ; a part pro- 

 ceeding north, through the haf, to Michilimackinac, and a part 

 going south, along the west shores of Lake Michigan, to Chicago, 

 the latitude of which is placed by Capt. Douglass in 41° 54' 06". 

 At this place, a further division took place. Dr. Wolcott, having 

 reached his station, remained. Governor Cass proceeded across 

 the peninsula of Michigan to Detroit on horseback, leaving Capt. 

 Douglass and myself to complete the survey of Lake Michigan. 

 We rejoined the northern party detached at Green Bay, under Mr. 

 Trowbridge and Mr. Doty, at Michilimackinac ; and, after repass- 

 ing the southern coast of Lakes Huron and St. Clair, reached 

 Detroit. 



Topographically, a very wide expanse of wilderness country 

 had been seen. The entire length of route computed to have 



* Pike's Expedition. This observation is corrected by Capt. Douglass to -17° 

 27' 10''': the point of observation being, however, a few miles south. 



