Description of the Locality of the Remains of Ancient Mining Operations, &c.

In casting the eye over a map of Lake Superior, a remarkable projection, in the form of an immense horn, will be observed jutting out from the south shore, and curving to the northeast until it ends in an irregular point.

This peninsula, which is called Keweenaw Point, is about eighty miles in length, and at the place where it joins the main land forty-five miles in width. Through the whole extent of this projection a belt of metalliferous trap formation extends, differing at various points in structure, and in the character of its contents. Along this belt, which is designated on the map by dotted lines, there are exhibited, throughout nearly its whole extent, a disturbance of the strata, and upheavals comprising a series of bluffs, rising abruptly from the two streams, Eagle and Montreal Rivers.

Within this belt, all the mining operations, ancient and modern, have been chiefly confined. The most remarkable feature of the district is the character of its metalliferous products, which occur, not in the condition of an ore of copper, but exclusively as native metal. This is met with in immense masses, in veins of smaller size, and in rounded nodules. The cutting of the masses is a tedious and costly process, and in some instances, even with all the appliances of modern art, requires several months before a single mass is entirely removed from the mine. The metal is sometimes almost entirely free from foreign matter, yielding when melted down in the furnace from 90 to 95 per cent. of copper.

The first actual mining operations, within historic times, were commenced near the forks of the Ontonagon, in 1761, by Alexander Henry, but under the peculiar circumstances they proved entirely abortive. In 1841, Dr. Douglas Houghton made a report to the Legislature of Michigan, in which the earliest definite information in regard to the occurrence of native copper on Lake Superior was given to the public. Shortly after this, mining operations were commenced in this region, explorers and speculators flocked to it from all quarters, and in 1845 the shores of Keweenaw Point were whitened with their tents.

In 1846 the excitement reached its climax, after which a reaction took place, and finally only half a dozen companies out of all that had been formed continued the operation of mining in good earnest.

The first public announcement, so far as we are aware, of the remains of ancient mines in the copper region is that by Mr. S. O. Knapp, agent of the Minnesota Mining Company, in 1848. Dr. Chas. T. Jackson brought forward the subject in his Geological Report to the United States Government, in 1849, and gave some interesting details of what had been discovered up to that time. Further mention of it was made by Messrs. Foster and Whitney, in their report in 1850, and several illustrations were given. Since then our knowledge of the subject has been much enlarged by the prosecution of mining operations on the very sites of the ancient works.

It must not, however, be supposed that our information is now complete. It is by no means an easy task to discover remains buried, as those of the ancient mines of

Lake Superior are, in extensive and dense forests, where the explorer can only see a few rods, or, perhaps, yards around him, and where there is seldom anything which rises sufficiently high above the surface to attract the eye.

They are, for the most part, merely irregular depressions in the soil, trenches, pits, and cavities; sometimes not exceeding one foot in depth, and a few feet in diameter. Thousands of persons had seen the depressions prior to 1848, who never suspected that they had any connection with the arts of man; the hollows, made by large trees overturned by the wind, being frequently as well marked as the ancient excavations. Besides this, there are natural depressions in the rocks on the outcrop of veins, formed by the decomposition of the minerals, that resemble the troughs of the ancient miners, as they appear after the lapse of centuries. There is not always a mound or ridge along the side of the pits, for most of the broken rock was thrown behind, nearly filling up the trenches. A mound of earth is as nearly imperishable as any structure we can form. Some of the tumuli of the west retain their form, and even the perfection of their edges at this day. But mere pits in the earth are rapidly filled up by natural processes. Some of those which have been reopened, and found to have been originally ten feet deep, are now scarcely visible. Others that have a rim of earth around the borders, or a slight mound at the side, and were at first very shallow, are more conspicuous at present than deep ones without a border.

There are, however, pits of such size as could not fail to surprise one at first view, were not the effect destroyed by the close timber and underwood with which they are surrounded. A basin-shaped cavity, 15 feet deep and 120 feet in diameter, would immediately attract the eye of the explorer were it properly exposed. But it is not unusual to find ten and twelve feet of decayed leaves and sticks, filling a trench, and no broken rock or gravel. In such cases a fine red clay has formed towards the bottom, a deposit from water, which indicates the long period of time since the excavation was made.

From the accompanying map it will be seen that the positions of the principal ancient mines correspond to those which are worked at present. There are three groups or centres of operation in both cases, one a little below the forks of the Ontonagon River, another at Portage Lake, and a third on the waters of Eagle River. Other works are known to exist, and more will probably be found; but we have probably discovered the most important ones within the district embraced by the map.

Although the old works are not always situated upon what would be considered good veins, yet they are regarded by practical miners as pretty sure guides to valuable lodes.

In the opening of our principal mines, we have followed in the path of our predecessors, but with much better means of penetrating the earth to great depths. The old miners performed the part of surface explorers.

In giving detailed descriptions of the antiquities of the mining country, we shall commence with those most easterly, near the extremity of Point Keweenaw, and proceed along the mineral range in the order of position to the southwest. There are, however, ancient works found over a much greater space than is included in the map.

The veins on Isle Royale, and near the north shore, opposite Point Keweenaw, were extensively wrought in olden times.

In the other direction, sixty and eighty miles to the southeast, in the iron region near Marquette are remains that are also ancient, and which will be noticed hereafter.

No doubt future examinations will bring others to notice on the continuation of the mineral range to the southwest, as it extends in that direction into Wisconsin.

DESCRIPTION OF THE SEVERAL WORKS.

1ST GROUP.

The Agate Harbor Company has an extensive property on the range south of Agate Harbor, on which there are reported to be Indian diggings, as these excavations are frequently called by the miners. They are well developed at the works of the Native Copper Company, on the northern slope of the range, and on the Northwest Company's grounds at their mines, south of the "Greenstone" cliffs. The same veins extend across both these locations, a distance of a mile and a half, indicated by the presence of old works.

At the Northwest Mine the pits are conspicuous, showing on the surface the position of three veins that have since been wrought. Stone mauls were abundant in them. Some of the pits had been made in a band of red conglomerate, which lies between the strata of greenstone (or crystalline) and amygdaloid trap. This conglomerate is composed of pebbles and boulders principally of red trap, cemented by argillaceous red sand, forming a very compact stratum, twelve to twenty feet thick. It here carries copper in small grains or pieces, near the veins; also crystallized calcareous spar and epidote.

The ancients did not neglect the most trifling indications of metal, but appear to have instituted a thorough investigation as to whether the copper existed in true veins, in metalliferous bands, or in detached nests. There is nothing remarkable in their operations at the “Native” Copper and the “Northwest" mines, except this closeness of pursuit, through all the veins and branches to their most minute extremities.

Waterbury Mine.-The works of this Company are situated about one mile and a half west of the Northwest Mine. A person passing to the interior from Eagle Harbor or anywhere along the northern shore of Point Keweenaw, and crossing the mineral range to the valley of the Little Montreal, witnesses everywhere the same topographical features. The mountain range rises from the lake level, in the distance of a mile, to an elevation of 500 and 600 feet; in the next mile the ascent is less precipitous, but the ground continues to rise from one to two hundred feet more. From the summit of the range there is along the whole line, from the extremity of the point to the Albion location, two miles west of the Cliff Mine, a vertical wall of naked trap rudely columnar, the upper edge, or crest, of which forms the summit of the range. This mineral front has the appearance of a vast upheaval from two to three hundred feet high facing the south, and about thirty

miles in length. The ground from the bottom of this wall rises gradually to the south until it reaches another range of about the same elevation, thus forming a long narrow valley, through which flow, in opposite directions, the Montreal and Eagle Rivers. From the summit of the perpendicular cliff at the Waterbury Mine this valley presents a view extremely picturesque, and such as is seldom seen by the traveller in other regions. The general contour of the valley is curvilinear, so that the eye, placed at the middle of an arc in the position above mentioned, takes in the boundary ridge on each side as well as the whole inclosure. At the Waterbury Mine, which is situated near the middle of the length of the valley, there is in the face of the vertical bluff an ancient artificial recess or cavern, which is twenty-five feet in horizontal length, fifteen feet high, and twelve feet in depth. In front of it is a pile of the excavated rock, on which are now standing, in full size, the forest trees common to this region. Some of the blocks of stone which were removed from the recess would probably weigh two or three tons, and must have required the use of levers to dislodge them from their original position. Beneath the surface rubbish the remains of a gutter or trough composed of cedar bark were discovered, the object of which was clearly to conduct off the water which was baled from the mines by wooden bowls, of which mention will be made hereafter. Portions of fine or pulverized copper scales remained in the upper end of this trough. After removing the water and decayed leaves at the bottom of the excavation a piece of white cedar timber was found, one end of which exhibited the marks of a cutting instrument like those of a narrow axe.

.

WATERBURY MINE, artificial cavern.-A. Crystalline or greenstone trap, dipping N. 280.-B. Amygdaloid trap.C. Talus of the bluff and drift.-a. Ancient rock excavation.-b. Rubbish thrown out of a.-d. Conglomerate bed. c c. Jointed chloritic bed.-e e. Inclined shaft of Waterbury Company.-2. Little Montreal River or

creek.

The above profile is made at right angles to the bluff, and shows the geological structure as seen from the western side. It would answer equally well for the North, West, North Western, Eagle River, Cliff, or any mine situated on the southern face of the coast range of Point Keweenaw.

The copper bearing amygdaloid (B) is separated from the crystalline or "Greenstone" trap (4) by a parting of conglomerate (d), which is however sometimes wanting, and its place supplied by a thin bed of red clay called “flucan "overlaid by a layer of quartz carrying specks of copper. This parting, whether it be of red conglomerate or of flucan and quartz, is known as the "slide," and sometimes (though improperly) is called a cross-course. The beds all dip northerly and at an angle of 28°. Resting immediately on the slide, and composing the inferior face of the greenstone stratum, is a bed of blackish-green chloritic rock (cc) very much jointed, which contains between its joints, in a leafy state and in its mass in a state more solid, scales, particles, and lumps of copper. This chloritic bed is from 12 to 15 feet thick, and in it the ancients worked forming this cavern. They did not operate on a vein at this place.

The Waterbury Company, encouraged by the labors of their predecessors, followed from the bottom of "a" along the surface of the conglomerate by an inclined shaft “E E” to a depth of 300 feet, measuring on the slide.

66

In removing a part of the old burrow B, Dr. Blake discovered several shovels, of white cedar, resembling the paddles in form now used by the Chippeway Indians in propelling their canoes. Had these been found elsewhere, they would have been regarded as ordinary paddles, but in this place they had evidently been used as shovels. This is also evident from the manner in which the blades are worn, as shown by the lines a a, bb, cc, in the annexed sketch.

α

α b с
b

Fig. 2.

α

WOODEN SHOVEL, 3 feet long-Waterbury Mine.—a a a. Original form.-b b. Partially worn.-c c. Worn obliquely.

The blades are more worn on the under side than the upper, as if the mineral had been scraped together and then shovelled out, as is the practice of the miners of the present day. The shovels which were found beneath the water level were sound in appearance, and the strokes of the tool by which they were formed remained perfectly distinct, but on being dried they shrunk very much, opening in long cracks, the wood retaining little of its original strength or hardness.

A birch tree, two feet in diameter, grew directly over one of these paddles. A portion of a wooden scoop, or bowl, was found in the pit, evidently intended to dip up and to pass water. Its edge had been worn, like the shovels, by scraping over the rock; but it was so much decayed that it fell to pieces when it was taken out. I examined the walls of this cavern minutely, hoping to find the marks of some tool of metal. The effects of blows of stone mauls were visible, and such is the hardness of the rock, that if drills or picks had been used upon it, I think the marks would be easily seen, particularly on that part which was protected from the atmosphere by water.

At one place something resembling the impression made by the point of a light sharp pick was discernible, but not very plain, and only in a single instance.