LAKE WINN1P E G. 



183 



small bay, near Big Swamp Point, the limestone is seen jutting out beneath heavy, 

 loose masses of crystalline rocks, some of which would weigh hundreds of tons. The 

 surfaces of many of the limestone slabs at this locality are crowded with well-pre- 

 served specimens of the characteristic fossil, Leptcena alternata. 



Before leaving Fort Garry, I obtained a fine specimen of chain coral ( CatenijJora 

 escharoides) , which was said to have been obtained either on the shores of Lake 

 Winnipeg, or in the vicinity. Thus, it appears that limestones of the age of the 

 Lower and perhaps Upper Silurian rocks of England, extend as far north as the 

 south shore of Lake Winnipeg, retaining not only the palaiontological features which 

 they possess in Wisconsin and Iowa, but much the same lithological character also. 

 There is reason to believe, too, that these calcareous beds of F. 3, abut on the 

 granites and syenites of this region of country, without the intervention of F. 1 and 

 F. 2 ; since no rocks referable to these latter formations were observed there in the 

 few miles between Big Swamp Point and the entrance of Winnipeg River, where 

 the crystalline rocks are unequivocally in place. 



However, such might very well exist, and be easily overlooked, or hidden from 

 view by the water and immense masses of erratics that line the shores, and rest 

 upon the upturned edges of the sedimentary beds. 



I am led to believe, from information obtained at Fort Alexander, that the same 

 limestone which we found in place at Poplar and Big Swamp Points, will be found 

 extending at least as far north as Rocky Point, and Isle La Biche, or Elk Island. 



DECHARGE 1)8 LA CAVE. 



As many geological details of the country immediately bordering on the northern 

 limits of the United States, have been given in the Narrative of Major Long's Expe- 

 dition, published in 1824 ; and, as the geology of Northern Minnesota will be treated 

 of more particularly in Dr. Norwood's Report, I shall, in order to avoid unnecessarily 

 increasing the bulk of this work, conclude this section with only a few general 

 remarks touching one or two important features of that country along my imme- 

 diate route of travel, in returning from the Lake of the Woods to Lake Superior, in 

 1848. 



