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% = W. W. Mather on the Meteorology, &c. 
The most remarkable dunes or hills of blown sand, observed, 
are those w.s.w. of Eagle Harbor, between there and Sand Bay, 
which are fifty feet or sixty feet high on the coast, and much 
higher in the interior, near the base of the hills; those near Ea- 
_ gle River to the west four to five miles ; and those at the mouth 
of Pic River on the Canada shore. Dunes of twenty feet to 
forty feet high are common in almost every part of the lake coast 
pr sand beaches are formed, and where the strong dry winds 
can sweep over a considerable length of beach. The highest and 
ont remarkable dunes are so situated as to demonstrate that the 
westerly and northwesterly winds are the prevailing ones, that 
blow with force enough to drift much sand. Mr. Schooleraft has 
described remarkable dunes on the lake coast, three hundred 
feet high,* between Grand Island and White Pish Point. All | 
who have coasted that shore, have observed them. 
- An estuary deposit at the mouth of Pic River, may also be ad- 
duced as an evidence of a former higher level of the lake. This 
is about twenty feet to forty feet above the lake, nearly level, 
and where the river was cutting it away, great numbers of fresh- 
water sabre shells were found, such as are now living in great 
numbers in the adjacent waters, and occur on the beach. This 
deposit is "Hot blown sand, as it is nearly level, while that near 
the beach is piled in hills sixty feet to seventy feet high, and 
continually encroaching upon the level estuary deposit, burying 
the forest on the landward side in its progress. 
ke Superior, so far as is known, does not show any indica- 
tion of having had any other outlet than that through which its 
surplus water now flows, and so far as the facts observed justify 
any conclusion, we may infer, that the lowering of level indicated 
by the preceding facts, may be ascribed to the gradual wearing 
down of its outlet at the Sault St. Marie. The rocks at this 
place are gray and red variegated sandstones highly indurated, 
which wear away with extreme slowness. ‘They are nearly hor- 
rizontal in position, and dip slightly to the west and northwest. 
The outlet in former times, when the lake was twenty feet or 
thirty feet higher, must have been two miles in width, but shal- 
low; the flat lands at the Portage of the Sault St. Marie, con- 
sist of gravel and boulder of almost every variety of rock ‘found 
on the shores of Lake Superior, intermixed with loam, and these 
materials rest on the flat and often smoothed surface of the sub- 
jacent sandstone. 
The facts considered as demonstrating a water level some 
hundred feet above the present level will be adduced in another 
article on the geology of that region. 
=. — 
* Am. Journal of Science, vol. xliv, p. 369. 
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