OR, VULCAN S PEAK. 63 itself. This inclination Mark fancied was owing to the circumstance that the water of the ocean had formerly en tered at the hole, in uncommonly high tides and tempests, arid washed the ashes which had once formed the bottom of the crater, towards the remote parts of the plain. These ashes had been converted by time into a soft, or friable rock, composing a stone that is called tufa. If there had ever been a cone in the crater, as was probably the case, it had totally disappeared under the action of time and the wear of the seasons. Rock, however, the bed of the crater could scarcely be yet considered, though it had a crust which bore the weight of a man very readily, in nearly every part of it. Once or twice Mark broke through, as one would fall through rotten ice, when he found his shoes covered with a light dust that much resembled ashes. In other places he broke this crust on purpose, always finding beneath it a considerable depth of ashes, mingled with some shells, and a few small stones. That the water sometimes flowed into this crater was evident by a considerable deposit of salt, which marked the limits of the latest of these floods. This salt had pro bably prevented vegetation. The water, however, never could have entered from the sea, had not the lava which originally made the outlet left a sort of channel that was lower than the surface of the outer rocks. It might be nearer to the real character of the phenomenon were we to say, that the lava which had broken through the barrier at this point, and tumbled iato the sea, had not quite filled the channel which it rather found than formed, when it ceased to flow. Cooling in that form, an irregular crevice was left, through which the element no doubt still occa sionally entered, when the adjacent ocean got a sufficient elevation. Mark observed that, from some cause or other, the birds avoided the crater. It really seemed to him that their instincts warned them of the dangers that had once environed the place, arid that, to use the language of sail ors, " they gave it a wide berth," in consequence. What ever may have been the cause, such was the fact ; few even flying over it, though they were to be seen in hundreds, in the air all round it.
