It must not be forgotten that before the arrival of white men, and even to this day in certain localities, copper appeared about as valuable as gold. If the Lake Superior mines had been gold instead of copper it would not greatly have enhanced the value of the product in the opinion of the Amerinds of the locality and their customers. They worked their way down into the rock which carried native copper and broke off nodules and fragments as they proceeded. Some of the pits were eighteen or twenty feet deep, and in one case a huge bowlder of copper was found lying on oak supports several feet from the bottom. This mass had been denuded of every projection, and the supposition generally has been that it was being elevated to the surface by means of the wood underpinning. This may have been the case, but it is possible that the underpinning was inserted as the miners went down on the vein, because the bowlder was too large to cut or handle. They therefore _left it where found_ and proceeded to mine under and around for the smaller pieces. The large one was ten feet long, three feet wide, nearly two feet thick, and weighed over six tons. Other bowlders of greater weight have been found, moved, as is supposed, a considerable distance from the original bed, but the same hypothesis might apply to these that is suggested above. The famous Ontonagon bowlder,[257] which was found on the river of that name, is a copper mass weighing somewhere near five tons and has been the cause of much speculation as to how it came there. The probability is that it was left by glacial action on the surface, not far from, if not on, the spot where found. It is not likely that the Amerinds would take the trouble to move so large a mass far. If they had possessed the power of cutting it up, they would have done it near its source, and the same remark applies to the bowlders of copper that it has been supposed they were trying to lift to the surface. Furthermore, if the Ontonagon bowlder were transported by them to its position, and if the large bowlders in the mines were destined for the surface and transportation in bulk, we ought to find somewhere else records or evidences of the presence of great bowlders, but nothing of the kind has been found; no such large copper mass has been discovered in any ruined Amerind town, or on any Amerind village or town site. It seems that the Ontonagon bowlder was a natural deposit. These huge masses of copper were troublesome to modern miners with the most approved machinery.