364. The large masses of rock so often met with at a distance from their original place, are one of the arguments used for the _debacle_. It has, however, been shown, that, supposing a form of the earth's surface considerably different from the present, especially, supposing the absence of the valleys which the rivers have gradually cut out, the transportation of such stones is not impossible, even by such powers as nature employs at present. Now, without the supposition that the surface was more continuous, and that its present inequalities did not exist, no force of torrents, whatever their velocity and magnitude may have been, could have produced this transportation. No force of water could raise a stone like the _pierre de goutté_ from the bottom of a valley, to the top of a steep hail. Indeed, if we suppose a great fragment of rock to be hurried along on a horizontal or an inclined plane, by the force of water, the moment it comes to a deep valley, and has to rise up over an ascent of a certain steepness, it will remain at rest; the water itself will lose its velocity, and the heavy bodies which it carried with it will proceed no farther. Thus, therefore, we have the following dilemma. If the surface is not supposed to have had a certain degree of uniformity in past times, a _debacle_ is insufficient for the transportation of stones: If it is supposed to have had that uniformity, a _debacle_ is unnecessary. 365. Another fact, which has been supposed favourable to the opinion of the action of great torrents at some former period, is, that in countries like that round Edinburgh, where whinstone hills rise up from among secondary strata, a remarkable uniformity is observed in the direction of their abrupt faces. Thus, in the country just mentioned, the steep faces generally front the west, whiles in the opposite direction, the slope is gentle, and the hills decline gradually into the plain. Hence it is supposed, that a torrent, sweeping from west to east, has carried off the strata from the west side of these hills, but, being obstructed by the whinstone rock, has left the strata on the east side in their natural place.