CARLTON COUNTY, 1899. N. H. WINCHELL. 



from the igneous materials which they contain. To these sandstones, therefore, the 

 name Potsdam is also extended. They are of the date of the waning stages of the 

 Keweenawan. 



During this eruptive epoch there was a gradual subsidence of the region. The 

 trap beds, more or less broken, the quartzyte and conglomerate of the Potsdam, the 

 Animikie, and even some of the Archean, went successively below the ocean's waters. 

 This event brought the later (Hinckley) sandstone nonconformable on these older 

 formations, but where the Keweenawan traps did not disturb the orderly sequence, 

 the Fond du Lac sandstones are presumably followed conformably by the later sand- 

 stone strata. The term Lower Cambrian includes the Animikie. The Middle Cam- 

 brian is represented, as supposed, by the Potsdam conglomerate and quartzyte, and 

 the Upper Cambrian includes the sandstones that accumulated after the cessation of 

 igneous disturbance, i. e., the Hinckley and St. Croix sandstones and the associated 

 limestones and shales to the commencement of the Lower Silurian. 



There are three glacial lakes represented in Carlton county, formed, like lake 

 Agassiz, by the waters resulting from the melting of the glaciers being dammed in by 

 the contour of the country, while the lower outlet was closed by the glacier. One 

 of these lakes was small, and was confined to Carlton county. It has been named 

 lake St. Louis, and its outlet, 523 feet above lake Superior, was through Otter Creek 

 and Mahtowa townships, uniting near Barnum with the Moose river valley, which is 

 tributary to the Kettle river and the Mississippi. The second glacial lake had an 

 outlet further south. This lake covered the Nemadji valley, and its outlet was 

 through T. 46-18, at a hight of 468 feet above lake Superior. The old channel is very 

 marked, but now nearly dry. The third glacial lake had its outlet by way of the 

 Brule-St. Croix valleys in Wisconsin. It appears to have been at least ten feet lower 

 than the outlet of lake Nemadji. N. H. w. 



