sa” Erratic Phenomena about Lake Superior. | 99 
Spreng every where undoubted evidence, that they were formed 
~ by the waters of the lake itself. : 
..._, As everywhere the lake shores are strewed with sand and peb- 
-. bles stranded within certain limits by the waves, the lowest 
4 ‘accumulations of loose materials remain within the action of 
~ heavy storms, and within such limit they are entirely deprived of 
vegetation. 
_ Next, another set of beaches is observed, consisting generally - 
_* of coarser materials, forming shelves above the reach of even the 
_% Severest storms, as shown by the scanty cryptogamus vegetation,” 
_ ; and a few small herbaceous plants which have grown upon them. . 
: ext, other beaches, retreating more and more from the shores, - 
* are observed, upon which an older vegetation is pe consisting 
of shrubs, small trees, and a larger number ofdifferent plants, 
among which extensive carpets of wonderful lichens sometimes 
spread over large surfaces of greater eftent. And the gentle slope 
_of some of the terraces shows that the lake must have stood at 
this level for a longer time, as higher banks rise precipitously 
above them, consisting also of loose materials, which must have 
been worn out and washed away, for a considerable time, by the 
action of the waves from the lake. In sucha manner, terrace above 
this volume. Its height has been determined by Mr. Logan, in 
his Geographical Report of Canada, page 10, where it is minutely 
described. I therefore refer to this account for further details. I 
would only mention here, that the first shelf, within the reach of 
the lake, consists of minute sand, and forms a narrow strip of 
Sterile ground along the water-edge; next, we have a slope of 
about 10°, followed by a flat terrace, extending for nearly fifty 
extends for several hundred paces, crowned by some irregular 
ridges at its summit, and along the rocky ledges which form the 
bay at the bottom of which this high gravel bank rises. 
In connection with these lake terraces, we must consider also 
the river terraces which present similar phenomena along their 
banks all around the lake, with the difference that they slope 
