44 THE VERMILION IRON-BEARING DISTRICT. 



Lake Vermilion is a g'ood illustration of the second kind of lake. Its 

 very irregular outline, with its islands and bays, is due chiefly to the g'eo- 

 logic structure and differential erosion of the various closelj^ folded rocks . 

 touching its shores. The reader is referred to the statement on page 432, 

 wherein attention is called to the fact that in many cases the islands are the 

 crests of anticlines of harder rocks, the basins between being in the slate 

 synclines; and also to the statement that the large bays on the east end of 

 the lake are found invariably to be in the younger Lower Huroniau rocks. 

 However, even in this western part of the district where the drift is rela- 

 tively heavy, the general trend of the long direction of the lakes corresponds 

 to the trend of the structural features; that is, it is about N. 60°-80° E. 

 These lakes in the western portion of the district have relatively large 

 drainage basins, and are usually bordered by low shores clothed with small 

 second-growth timber. Near these shores and back from them within their 

 drainage basins one yerj commonly finds swamps of considerable extent, 

 which are not very much above the lake level. The water of the lakes 

 is clear but is almost invariably tinged by the coloring matter brought in 

 from these tributary swamps. This coloring varies much in intensity in the 

 different lakes, and although the writer's observations extended over only a 

 portion of the year — the months of July, August, September, and into 

 October — it was very noticeable that the intensity of the coloring varied 

 in the same body of water, being less in the late fall, when the water was 

 low, than in the early summer, just after the heavy rains, when the swamps 

 and streams were flooded. Sometimes the organic coloring matter is so 

 plentiful that a bucketful of the water shows a decided brown color. Such 

 waters, although clear, are not very transparent. It is almost impossible at 

 times to distinguish dai'k bodies 6 inches below the surface of such water. 

 Canoeing in smooth water of this nature is somewhat hazardous; the bow- 

 man, even when keeping a sharp lookout, can scarcely see the reefs and 

 snags in the water until he is upon them, whereas in rough water their 

 presence is shown by the way in which the water breaks on them. 



The lakes in the eastern part of the district offer a striking contrast to 

 those in the western portion which have just been described. They are, 

 with the exception of some of the largest lakes, almost uniformly long and 

 narrow, are surrounded by high and bare rocky cliff's, and lie in distinctly 

 structural basins. Later a number of instances will be cited (p. 432) to show 



