You may imagine our surprise when we found, within a ride of Clermont, a set of volcanic phenomena entirely unknown to Buckland, Scrope, or the natives here. A volcanic cone, with a stream of basaltic lava issuing out on both sides, and flowing down to the gorge of the Sioule. This defile was flanked on both sides by precipitous cliffs of gneiss, and the river’s passage must have been entirely choked up for a long time. A lake was formed, and the river wore a passage between the lava and the granitic schist, but the former was so excessively compact, that the schist evidently suffered most. In the progress of ages, the igneous rock, one hundred and fifty feet deep, was cut through, and the river went on and ate its way, thirty-five, forty-five, and in one place eighty-five feet into the subjacent granitic beds, leaving on one bank a perpendicular wall of basaltic lava towering over the gneiss. In the Vivarrais, where similar phenomena had been observed, Herschel had remarked a bed of pebbles between the lava and the gneiss, marking the ancient river-bed, but Buckland endeavoured to get over this difficulty by saying that these pebbles might have covered a sloping bank when the river filled the valley, and that this bank may have always been high above the river bed; for if the sloping sides of a valley, said the Professor, be covered with pebbles, as they often are, and the valley is filled with lava, and then the lava cut through and partially removed, there will of course be a line of pebbles at the junction of the lava and the rock beneath, but these pebbles will not mark an ancient river bed. Now, unluckily for the doctor in this case, he has no loophole; an old lead mine, said to have been worked by the Romans, happens to have exactly laid open the line of contact, and the pebble bed of the old river is seen going in under the lava, horizontally, for nearly fifty feet. This is an astonishing proof of what a river can do in some thousands or hundred thousand years by its continual wearing. No deluge could have descended the valley without carrying away the crater and ashes above.