"The factory was in the Territories, three or four hundred miles north of your mine, and the agent sent him out, with a dog-train and two Indians, to collect some furs.

They had to make a long journey, and were coming back, short of food, when they camped one evening beside a frozen creek.

The water had worn away the face of a small cliff, and the frost had recently split off a large slab.

That left the strata cleanly exposed, and my father noticed that near the foot of the rock there was a different-colored band.

They were making camp in the snow then, but he went back afterwards when the moon rose and the Indians were asleep, and broke off a number of bits.