But Prof. Stonehenge was right too; it was a stone of the chalcedonic family, resembling sardonyx, except in color; others, similar to it both in a natural state and wrought into arrow-heads, had been found along the shores of Lake Superior. This seemed to have been brought away from its associates by some wandering tribe, for it had been discovered in Central Illinois. The nearest point at which other relics belonging to the same period had been found was the site of Fort Crèvecoeur, near Starved Rock, Illinois. After all, the stone only differed from the arrow-heads of Lake Superior in its beautiful carving and unprecedented size--and, ah, yes! there was another difference, the mystery of its discovery. No other skeleton among all the buried braves unearthed by scientific research at Crèvecoeur had been found with a gem for a heart--a gem that glittered not on the breast, but within a chest hooped with human bone. Mrs. Dalliba had just remarked that she had never felt so strong a desire to possess and wear any jewel as now; but when Prof. Stonehenge told how the uncanny thing rattled within the white ribs of the skeleton in which it was found, she allowed the gem to slip from her hand, while something of its own pale green flickered in the disgusted expression which quivered about the corners of her mobile mouth. The cameo was a mystery which had baffled geologist, antiquarian, and sculptor alike, for Father Francis Xavier had gone down to his grave with his secret and his cameo hidden in his heart. He had kept both well for two centuries, and when the heart crumbled in dust it took its secret with it, leaving only the cameo to bewilder conjecture.