where once the house had been which Murdock took from Joyce, and so met his doom. Here there was a great pool of water—and indeed all throughout the ravine were places where the stream broadened into deep pools, and again into shallow pools where it ran over the solid bed of rock. As we passed up, Dick hazarded an explanation or a theory:—
"Do you know it seems to me that this ravine or valley was once before just as it is now. The stream ran down it and out at the Shleenanaher just as it does now. Then by some landslips, or a series of them, or by a falling tree, the passage became blocked, and the hollow became a lake, and its edges grew rank with boggy growth; and then, from one cause and another—the falling in of the sides, or the rush of rain storms carrying down the detritus of the mountain, and perpetually washing down particles of clay from the higher levels—the lake became choked up; and then the lighter matter floated to the top, and by time and vegetable growth became combined. And so the whole mass grew cohesive and floated on the water and slime below. This may have occurred more than once. Nay, moreover, sections of the bog may have become segregated or separated by some similarity of condition affecting its parts, or by some formation of the ground, as by the valley narrowing in parts between walls of rock so that the passage could be easily choked. And so, solid earth formed to be again softened and demoralized by the later mingling with the less solid mass above it. It is
