SOUTH SHORE OF LAKE S U P E It I O It. 



269 



crystalline rocks are embedded in the upper stratum. This is the character of the 

 shore to the mouth of Bois Brule River. The preceding section of a bluff, about 

 half a mile above Cranberry Bay, will convey a correct idea of the disposition of the 

 more recent deposits overlying the sandstone. 



The prevailing colour of the sandstone on the south shore is red, but at many 

 points the lower beds are drab-colourecl ; and there are frequent alternations of red, 

 white, and drab-coloured layers. Some of the beds resemble the sandstones of the 

 Chippewa, St. Croix, and Kettle Rivers. Many of the beds in this whole region 

 are pebbly, and frequently contain such numbers of large pebbles as to give them 

 the character of a conglomerate. The lower stratum in the vicinity of the above 

 section is of considerable thickness, and in the upper part contains numerous large, 

 round, smooth pebbles, and among them many of a reddish-coloured quartzose por- 

 phyry, from two to three inches in diameter. Above this are thin strata of shaly 

 sandstone, generally very coarse-grained, and even pebbly, with numerous white 

 stripes and spots. Sometimes thin seams of slightly coherent pebbles, small and 

 rounded, are interposed between the beds. In general, these rocks are very loosely 

 cemented, and when exposed to the weather, soon disintegrate. 



The following section occurs about three hundred yards above the mouth of Cran- 

 berry River, and is given here for future reference, when the metamorphosed beds 

 north of the Lake come to be considered. 



1. The lowest stratum is exposed seven feet above the present level of 



the Lake, and is composed of a rather coarse-grained red sand, with 

 buff-coloured stripes traversing it, from one to three inches thick. The 

 upper part is banded by red and white stripes, from one-fourth to half 

 an inch in thickness, marking lines of deposition, which dip about 12° 

 to the reverse of the general dip of the rock ; while other lines, above 

 these, dip in the same direction at an angle of 45°. (The general dip 

 of the rocks in this section is southeast from 3° to 4°), . . 7 



2. Red sandstone, rather more compact, but soft, coarse, and easily 



aifected by the weather, ...... 3 



3. A very coarse, dark red, sandy shale, extremely soft and decomposable, 4 



4. Sandstone — yellowish red in the lower part, red in the upper, compact 



in some places, but soft and shaly-like in others, . . 5 



5. Alternations of compact and shaly layers, .... 4 



6. Sandstone — partly compact and partly shaly, showing numerous cross 



lines of deposition ; weathers easily ; full of small, irregular, roundish 

 spots of a yellow colour; much broken by joints. The upper surface 

 of this bed contains large pebbles of rounded quartz and trap rocks, . 5 



7. Red sandstone — rather compact ; overhangs the lower beds in the 



escarpments ; the edges are sharper, and the angles better defined, 3 



8. Red clay, ........ 16 



9. Sandy marl, ........ 10 



The marl-beds increase in thickness as you recede from the shore. In a small 

 ravine, about three hundred yards distant from the Lake, the clay and marl-beds 

 measured fifty-eight feet. 



Few of the beds exposed in the escarpments along the shore can be traced for 



