Detroit, Oct. 13th, 1843.
The so-called copper rock of Lake Superior was brought to this place, a day or two since, in a vessel from Sault Ste-Marie, having been transported from its original locality, on the Ontonagon river, at no small labor and expense. It is upwards of twenty-three years since I first visited this remarkable specimen of native copper, in the forests of Lake Superior. It has been somewhat diminished in size and weight, in the meantime, by visitors and travellers in that remote quarter; but retains, very well, its original character and general features.
I have just returned from a re-examination of it in a store, in one of the main streets of this city, where it has been deposited by the present proprietor, who designs to exhibit it to the curious. Its greatest length is four feet six inches; its greatest width about four feet; its maximum thickness eighteen inches. These are rough measurements with the rule. It is almost entirely composed of malleable copper, and bears striking marks of the visits formerly paid to it, in the evidences of portions which have from time to time been cut off. There are no scales in the city large enough, or other means of ascertaining its precise weight, and of thus terminating the uncertainty arising from the several estimates heretofore made. It has been generally estimated here, since its arrival, to weigh between six and seven thousand pounds, or about three and a half tons, and is by far the largest known and described specimen of native copper on the globe. Rumors of a larger piece in South America are apocryphal.
The acquisition, to the curious and scientific world, of this extraordinary mass of native metal is at least one of the practical results of the copper-mining mania which carried so many adventurers northward, into the region of Lake Superior, the past summer (1843). The person who has secured this treasure (Mr. J. Eldred) has been absent, on the business, since early in June. He succeeded in removing it from its diluvial bed on the banks of the river, by a car and sectional railroad of two links, formed of timber. The motive power was a tackle attached to trees, which was worked by men, from fourteen to twenty of whom were employed upon it. These rails were alternately moved forward, as the car passed from the hindmost.
In this manner the rock was dragged four miles and a half, across a rough country, to a curve of the river below its falls, and below the junction of its forks, where it was received by a boat, and conveyed to the mouth of the river, on the lake shore. At this point it was put on board a schooner, and taken to the falls, or Sault Ste-Marie, and thence, having been transported across the portage, embarked for Detroit. The entire distance to this place is a little within one thousand miles; three hundred and twenty of which lie beyond St. Mary's.
What is to be its future history and disposition remains to be seen. It will probably find its way to the museum of the National Institute in the new patent office at Washington. This would be appropriate, and it is stated that the authorities have asserted their ultimate claim to it, probably under the 3d article of the treaty of Fond du Lac, of the 5th of August, 1826.
I have no books at hand to refer to the precise time, so far as known, when this noted mass of copper first became known to Europeans. Probably a hundred and eighty years have elapsed. Marquette, and his devoted companion, passed up the shores of Lake Superior about 1668, which was several years before the discovery of the Mississippi, by that eminent missionary, by the way of the Wisconsin. From the letters of D'Ablon at Sault Ste-Marie, it appears to have been known prior to the arrival of La Salle. These allusions will be sufficient to show that the rock has a historical notoriety. Apart from this, it is a specimen which is, both mineralogically and geologically, well worthy of national preservation.
It is clearly a boulder, and bears marks of attrition from the action of water, on some parts of its rocky surface as well as the metallic portions. A minute mineralogical examination and description of it are required. The adhering rock, of which there is less now than in 1820, is apparently serpentine, in some parts steatitic, whereas the copper ores of Keweena Point on that lake, are found exclusively in the amygdaloids and greenstones of the trap formation. A circular depression of opaque crystalline quartz, in the form of a semi-geode, exists in one face of it; other parts of the mass disclose the same mineral. Probably 300 lbs. of the metal have been hacked off, or detached by steel chisels, since it has been known to the whites, most of this within late years.
IX.