The Straights of St. Marie are about forty miles long, bearing south-east, but varying much in their breadth. The current between the Falls and Lake Huron is not so rapid as might be expected, nor do they prevent the navigation of ships of burden as far up as the island of St. Joseph.
It has been observed by travellers that the entrance into Lake Superior, from these Straights, affords one of the most pleasing prospects in the world. The place in which this might be viewed to the greatest advantage, is just at the opening of the lake, from whence may be seen on the left, many beautiful little islands that extend a considerable way before you; and on the right, an agreeable succession of small points of land, that project a little way into the water, and contribute, with the islands, to render this delightful bason (as it might be termed) calm and secure from the ravages of those tempestuous winds by which the adjoining lake is frequently troubled.
Lake Huron, into which you now enter from the Straights of St. Marie, is the next in magnitude to Lake Superior. It lies between forty-two and forty-six degrees of north latitude, and seventy-nine and eighty-five degrees of west longitude. Its shape is nearly triangular, and its circumference about one thousand miles.
On the north side of it lies an island that is remarkable for being near an hundred miles in length, and no more than eight miles broad. This island is known by the name of Manataulin, which signifies a Place of Spirits, and is considered by the Indians as sacred as those already mentioned in Lake Superior.
About the middle of the south-west side of this lake is Saganaum Bay. The capes that separate this bay from the lake, are about eighteen miles distant from each other; near the middle of the intermediate space stand two islands, which greatly tend to facilitate the passage of canoes and small vessels, by affording them shelter, as without this security it would not be prudent to venture across so wide a sea; and the coasting round the bay would make the voyage long and tedious. This bay is about eighty miles in length, and in general about eighteen or twenty miles broad.
Nearly half way between Saganaum Bay and the north-west corner of the Lake lies another, which is termed Thunder Bay. The Indians, who have frequented these parts from time immemorial, and every European traveller that has passed through it, have unanimously agreed to call it by this name, on account of the continual thunder they have always observed here. The bay is about nine miles broad, and the same in length, and whilst I was passing over it, which took me up near twenty-four hours, it thundered and lightened during the greatest part of the time to an excessive degree.
There appeared to be no visible reason for this that I could discover, nor is the country in general subject to thunder; the hills that stood around were not of a remarkable height, neither did the external parts of them seem to be covered with any sulphureous substance. But as this phænomenon must originate from some natural cause, I conjecture that the shores of the bay, or the adjacent mountains, are either impregnated with an uncommon quantity of sulphureous matter, or contain some metal or mineral apt to attract in a great degree the electrical particles that are hourly borne over them by the passant clouds. But the solution of this, and those other philosophical remarks which casually occur throughout these pages, I leave to the discussion of abler heads.
The fish in Lake Huron are much the same as those in Lake Superior. Some of the land on its banks is very fertile, and proper for cultivation, but in other parts it is sandy and barren. The promontory that separates this lake from Lake Michegan, is composed of a vast plain, upwards of one hundred miles long, but varying in its breadth, being from ten to fifteen miles broad. This track, as I have before observed, is divided into almost an equal portion between the Ottowaw and Chipéway Indians. At the north-east corner this lake has a communication with Lake Michegan, by the Straights of Michillimackinac already described.
I had like to have omitted a very extraordinary circumstance relative to these Straights. According to observations made by the French, whilst they were in possession of the fort, although there is no diurnal flood or ebb to be perceived in these waters, yet, from an exact attention to their state, a periodical alteration in them has been discovered. It was observed that they arose by gradual, but almost imperceptible degrees till they had reached the height of about three feet. This was accomplished in seven years and a half; and in the same space they as gently decreased, till they had reached their former situation; so that in fifteen years they had completed this inexplicable revolution. At the time I was there the truth of these observations could not be confirmed by the English, as they had then been only a few years in possession of the fort; but they all agreed that some alteration in the limits of the Straights was apparent. All these lakes are so affected by the winds, as sometimes to have the appearance of a tide, according as they happen to blow; but this is only temporary and partial.
A great number of the Chipéway Indians live scattered around this Lake, particularly near Saganaum Bay. On its banks are found an amazing quantity of the sand cherries, and in the adjacent country nearly the same fruits as those that grow about the other lakes.