Superior, which is appended to this report, and which, it is believed, contains most correct and valuable information.

As yet, beyond the mining stations and the village at the Sault, Lake Superior has no towns or places of business except the points for shipping the mineral products of her soil, and receiving the supplies necessary to the subsistence of the men and animals employed in the exploitation of her treasures. Nor beyond this has she any trade, unless it be the exportation of her white-fish and lake trout, which are unequalled by any fish in the world for excellence of flavor and nutritious qualities.

The only inlet for merchandise, or outlet for the produce of this vast lake, and the wide regions dependent on it, is the portage around the Sault, across which every article has to be transported at prodigious labor and expense; whereas, by a little less exclusive devotion to what are deemed their own immediate interests, on the part of the individual States of the Union, and a little more activity and enterprise on that of the general government, an easy channel might be constructed at an expense so trivial as to be merely nominal, the results of which would be advantages wholly incalculable to the commerce of all the several States, to the general wealth and well-being of the nation, and to the almost immediate remuneration of the outlay to the general government by the increased price of, and demand for, the public lands in those regions.

Geology, Mineralogy, and Topography of the lands around Lake Superior; by CHARLES T. JACKSON, M. D., late United States Geologist and Chemist, Assayer to the State of Massachusetts, and late Geologist to the States of Maine, New Hampshire, Rhode Island, and for the public lands of Massachusetts.

Lake Superior is the largest sheet of fresh water on the face of the globe, and is the most remarkable of the great American lakes, not only from its magnitude, but also from the picturesque scenery of its borders, and the interest and value attaching to its geological features. As a mining region it is one of the most important in this country, and is rich in veins of metallic copper and silver, as well as in the ores of those metals. At the present moment it may be regarded as the most valuable mining district in North America, with the exception only of the gold deposites of California.

This great lake is comprised between the 46th and 49th degrees of north latitude, and the 84th and 92d degrees of longitude, west of Greenwich. Its greatest length is 400 miles; its width in the middle is 160 miles, and its mean depth has been estimated at 900 feet. Its surface is about 600 feet above the level of the Atlantic ocean, and its bottom is 300 feet below the level of the sea. The ancient French Jesuit Fathers, who first explored and described this great lake, and published an account of it in Paris in 1636, describe the form of its shores as similar to that of a bended bow, the northern shore being the arc, and the southern the cord, while Keweenaw Point, projecting from the

This graphic

southern shore to the middle of the lake, is the arrow. description is illustrated by a map, prepared by them, which displays the geographical position of the shores of this great lake with as much fidelity as most of the common maps of our own day, and proves that those early explorers were perfectly familiar with its shores, and knew how to make geopraphical surveys with considerable exactness. Reference to a former report to the government of the United States, by myself, (31st Congress, 1st session, Ex. Doc. No. 5, part 3d, Washington, 1849,) fully demonstrates how much was known to the early French explorers, of the geography and mineral resources of Lake Superior and the regions circumadjacent; and that report will be found, notwithstanding some omissions and interpolations, for which I do not hold myself responsible, to contain much that will tend to throw light on the mineral resources of the public lands lying along the southern shores of the lake.

The coast of Lake Superior is formed of rocks of various kinds and of different geological groups. The whole coast of the lake is rock-bound; and in some places, mountain masses of considerable elevation rear themselves from the immediate shore, while mural precipices and beetling crags oppose themselves to the surges of this mighty lake, and threaten the unfortunate mariner, who may be caught in a storm upon a lee-shore, with almost inevitable destruction. Small coves, or boatharbors, are abundantly afforded by the myriads of indentations upon the rocky coast; and there are a few good snug harbors for vessels of moderate capacity, such as steamboats, schooners, and the like. Isle Royale, though rarely visited by the passing vessels, affords the best harbors. Keweenaw Point has two bays in which vessels find shelter, viz: Copper harbor and Eagle harbor. Adequate protection may be found from the surf under the lee of the Apostle islands, at La Pointe ; and there is tolerable anchorage at the Sault de Ste. Marie, the port of embarcation upon St. Mary's river, at the outlet of the lake.

There are but few islands in Lake Superior; and in this respect it differs most remarkably from Lake Huron, which is thickly dotted with isles and islets, especially on its northern shore.

Owing to the lofty crags which surround Lake Superior, the winds sweeping over the lake impinge upon its surface so abruptly as to raise a peculiarly deep and combing sea, which is extremely dangerous to boats and small craft. It is not safe, on this account, to venture får out into the lake in batteaux; and hence voyageurs generally hug the shore, in order to be able to take land in case of sudden storms. During the months of June, July and August, the navigation of the lake is ordinarily safe; but after the middle of September great caution is required in navigating its waters, and boatmen of experience never venture far from land, or attempt long traverses across bays. Their boats are always drawn far up on the land at every camping-place for the night, lest they should be staved to pieces by the surf, which is liable at any moment to rise and beat with great fury upon the beaches. The northern or Canadian shore of the lake is most precipitous, and consequently most dangerous to the navigator. On the south shore, again, the sandstone cliffs which rise in mural or overhanging precipices, directly from the water's edge for many miles, afford no landing

places. This is the case especially along the cliffs at the Pictured Rocks, and on the coast of Keweenaw bay, called l'Anse by the French voyageurs.

On the coast of Isle Royale there are beautiful boat harbors scattered along its whole extent on both sides of the island; and at its easterly extremity the long spits of rocks, which project like fingers far into the lake, afford abundant shelter for boats or small vessels, while, at the western end of the island, there is a large and well sheltered bay called Washington harbor.

Near Siskawit bay the navigator must beware of the gently-shelving red sandstone strata which run for many miles out into the lake, with a few feet only of water covering them. Rock harbor, on the south side of the island, is a large and perfectly safe harbor for any vessels, and has good holding-ground for anchorage, with a very bold shore, while the numerous islands, which stand like so many castles at its entrance, protect it from the heavy surges of the lake. The whole aspect of this bay is not unlike that of the bay of Naples, though there is no modern volcano in the back-ground to complete the scene.

None of the American lakes can compare with Lake Superior in healthfulness of climate during the summer months, and there is no place so well calculated to restore the health of an invalid who has suffered from the depressing miasms of the fever-breeding soil of the southwestern States. In winter the climate is severe, and at the Sault Ste. Marie, mercury not unfrequently freezes; but on Keweenaw Point, where the waters of the lake temper the chillness of the air, the cold is not excessive, and those who have resided there during the winter, say that the cold is not more difficult of endurance than in the New England States. Heavy snows fall in mid-winter on this promontory, owing to its almost insular situation; but the inhabitants are well skilled in the use of snow-shoes, so that snow is not regarded as an obstacle to the pedestrian, while, on the newly-made roads, the sleds and sleighs soon beat a track, on which gay winter parties ride and frolic during the long winter evenings of this high northern latitude. From researches which I have made, it appears that the mean annual temperature at Copper Harbor, on Keweenaw Point, is 42°; and from my experiments on the temperature of the lake, at different seasons of the year, the waters of this great lake are shown to preserve a constant temperature of about 391 or 40° F., which is that of water at its maximum density. It is known that Lake Superior never freezes in the middle, nor anywhere except near its shores, from which the ice very rarely extends to more than ten or fifteen miles distance. Occasionally, in severe winters, the ice does extend from the Canada shore to Isle Royale, which is from fifteen to twenty miles distant; so that the caribou and moose cross over on it to the island, whither the Indian hunters sometimes follow them over the same treacherous bridge, liable, although it is, to be suddenly broken into fragments by the surges of the lake. By the action of drifting ice, not only have boulders of rocks and of native copper been transported far from their native beds, and deposited upon the shore at distant places; but even animals, such as squirrels, rabbits, deer, moose, caribou, and bears, have thus navigated the waters of Lake Superior, and been landed on islands to which

they could not otherwise have gained access. The mouth of every river on the lake shore reveals, by the debris brought down by ice in the spring freshets, the nature of the rocks and minerals which occur in its immediate banks or bed; and thus indicates to the explorer the proper places where to search for ores or metals.

The early French explorers noticed the fact of the transportation of masses of native copper and rock by drift-ice, but they made no use of these facts to discover the native deposites of metals in the rocks which border on the rivers. It was by following the hint drawn from these traces that my assistant and myself were enabled, in 1844 and 1845, to discover, and make known to the country, those valuable mines, which have so astonished the world by their metallic contents, and which subsequently induced the government of the United States to undertake a geological survey of that territory, with the conduct of which I was charged by the Hon. Robert J. Walker, late Secretary of the Treasury, and which I effected, so far as it was possible to do so, before my labors were brought to an abrupt conclusion, by circumstances over which I had no control.

To the construction of a canal around the falls of the Sault Ste. Marie, one of the principal obstacles will be found in the winter's ice, against which the locks at the entrance to the canal must be guarded, or the work, however strong, will be overturned and destroyed. Vessels of any considerable burden cannot approach the shore nearer than about half a mile. The canal must, therefore, be carried out into the water to that distance, and the form of the ice-breakers, guards, or mole, must be such as to allow the ice to rise over them, and not to press against perpendicular walls. This is to be done by giving a proper slope, or bevel, to the walls, so that the ice will ride up them and break into pieces. By this method the harbor and entrance locks may be sufficiently protected against the driving and expanding ice of the lake and St. Mary's river.

The opening of a ship-canal between Lake Superior and the lower lakes is one of the most important enterprises of the day, and it is only to be regretted that Congress has thought it best to appropriate land instead of applying money directly to the execution of this great work, which may now be delayed for some time, to the great disadvantage of the country at large. So soon as the canal above mentioned shall be completed, the summer tour of travellers will be extended to a cruise around Lake Superior, and from La Pointe many will cross over to the Falls of St. Anthony, on the Mississippi river; and thus explorers will find it easy to gain access to remote regions, now seldom visited by white men. The importance of this enterprise can hardly be overestimated, and its consequence will be the vast facilitation and increase of the commerce of Lake Superior, and the incalculable enhancement of the value of the public lands, while a tide of immigration may be looked for from Norway, Sweden, and the north of Europe, as well as from the New England States, pouring into the northwestern wilderness, and subduing the forests, and extending far and wide the area of freedom and civilization.

The time will doubtless come when a canal or railway will be made to the Falls of St. Anthony; and possibly we may see the trade of Hud

son's bay flowing into the United States, through Lake Superior and our other great lakes and rivers. For that great bay is but fifteen days' canoe voyage from Lake Superior, and the portages are few and not long, so that the British Hudson's Bay Fur Company carry on constant communication with their factories upon the bay from their posts upon Lake Superior; and their agents at the British posts in Oregon travel from their stations on the borders of the Pacific ocean, by way of Hudson's bay and Lake Superior, on their route to Great Britain. This northern region has unfortunately been always, hitherto, undervalued. It is now known to be one of the most important mineral regions in America; and it should be borne in mind that there are deposites of native copper on Copper Mine and McKenzie's rivers, in the same kinds of rock that contain the stupendous lodes of this metal on Keweenaw Point and the Ontonagon rivers. Every means that tend to carry our population farther northward, will tend to bring to light and to practical utility the mineral treasures of those regions; while trade in furs and seal-skins will be brought nearer to us by enterprising men, it matters not whether of the British provinces or of the United States of America. The time is now come when the public faith is settled on the value of mineral preductions; and it is understood that good working mines are sure to command and reward the energies of capitalists and miners, since it is proved that mining is liable to no greater risks of failure than ordinary mercantile enterprises, provided due precaution be exercised by the adventurers in the selection of their mines and in working them to advantage.

ROCKS OF LAKE SUPERIOR LAND DISTRICT.

On approaching the Sault Ste. Marie by the St. Mary's river the geologist has an opportunity of discovering the age of the sandstone strata, by observing that the limestones of Saint Joseph's island, and of the other numerous isles in that river, are rocks of the Devonian group, and contain the characteristic fossils by which that rock is determined to be the equivalent of those of Eifel, as has been fully proved by Mons. Jules Marcou, the geologist sent to the United States by the government of France, to make collections for the Museum of Geology in the Jardin des Plantes of Paris. These Devonian rocks, like those of Mackinac, have been mistaken by two geologists who have reported upon this district, for Siberian limestones; by whom the geological position of the sandstone of the Sault Ste. Marie has also been mistaken, in their supposing that it passed beneath these Devonian rocks, when it in reality is above them, as it is seen to rest horizontally around Silurian limestone, near Sturgeon river, on Keweenaw Point, beneath which it cannot pass, considering the fact that the limestone in question has a dip of thirty degrees from the horizon, while the sandstone at that place is quite horizontal.

It is obvious, then, that the red and gray sandstones of Lake Superior are above Devonian rocks, and therefore cannot be older than the coal formation; while from their lithological characters they appear to belong to the Permian system of Verneuil and Murchison. Above the Sault we see these red and gray sandstones dipping at a gentle angle into the lake, showing that they do in fact dip directly opposite to the direction