In several spots along the top of the eastern side of the gorge (we were now on the western) might be seen stakes of wood driven into the earth.
In these spots the earth had not given way, but throughout the whole extent of the face of the precipice from which the mass had fallen, it was clear, from marks left in the soil resembling those made by the drill of the rock blaster, that stakes similar to those we saw standing had been inserted, at not more than a yard apart, for the length of perhaps three hundred feet, and ranging at about ten feet back from the edge of the gulf.

Strong cords of grape vine were attached to the stakes still remaining on the hill, and it was evident that such cords had also been attached to each of the other stakes.

I have already spoken of the singular stratification of these soapstone hills; and the description just given of the narrow and deep fissure through which we effected our escape from inhumation will afford a further conception of its nature.
This was such that almost every natural convulsion would be sure to split the soil into perpendicular layers or ridges running parallel with one another, and a very moderate exertion of art would be sufficient for effecting the same purpose.

Of this stratification the savages had availed themselves to accomplish their treacherous ends.

There can be no doubt that, by the continuous line of stakes, a partial rupture of the soil had been brought about probably to the depth of one or two feet, when by means of a savage pulling at the end of each of the cords (these cords being attached to the tops of the stakes, and extending back from the edge of the cliff), a vast leverage power was obtained, capable of hurling the whole face of the hill, upon a given signal, into the bosom of the abyss below.