The construction of the earthen defences found in the valley of the Ohio and along the Mississippi evinces that those who erected them had great proficiency in engineering and military skill. They comprised all the parts of a systematic defence,--walls, ramparts, fosses, intrenchments, and even the lookout, corresponding to the _barbican_ in the British system of the Middle Ages. So that it may be asked, in the language of Dr. S. P. Hildreth, a zealous antiquarian of Marietta, Ohio, "Of what age, or of what nation, was this race that once inhabited the territory drained by the Ohio? From what we see of their works, they must have been acquainted with some of the fine arts and sciences. They have left us perfect specimens of circles, squares, octagons, parallel lines, on a grand and noble scale; and, unless it can be proved that they had intercourse with Asia or Europe, we must attribute to them the art of working metals." But the red race knew nothing of the art or science of smelting raw ores. Their copper instruments were beaten into shape from the native metal, and these at best were very rare and rude. The hundreds and thousands of relics in the various metals, many curiously finished, found in the valleys of the Ohio and Mississippi, in mounds and caves, must, therefore, be the product of another people. Nor is it necessary to go back to dim or immemorial ages to account for their origin. The Welsh are the best miners and workers in metals in the world. The Phoenicians carried on a large trade in the metals with the inhabitants of the British Isles centuries before the Christian era, and their mines of iron, copper, tin, etc., have since enriched the British Empire. The mines of the Upper Lake regions were doubtless worked by the Welsh in the thirteenth, fourteenth, and fifteenth centuries, all the evidences seeming to allow four or five hundred years since their opening. Old trees showing three hundred and ninety-five rings of annual growth have been found standing among the débris at the surface of some of these mines. Huge chunks of copper, in some cases weighing six tons, have been lifted out of their beds by finished tools and mining appliances.