surface; or if the bank or bed of clay lay on the surface of one shelving rock, the water would naturally drain to the lowest point and the upper land would be shallow in proportion."
"But," I ventured to remark, "if this be so, one of two things must happen; either the water would wear away the clay so quickly, that the accumulation would not be dangerous, or else the process would be a very gradual one, and would not be attended with such results as we are told of. There would be a change in the position of the bog, but there would not be the upheaval and complete displacement and chaos that I have heard of, for instance, with regard to this very bog of Knockcalltecrore.
"Your 'if' is a great peacemaker! If what I have supposed were all, then the result would be as you have said; but there are lots of other supposes; as yet we have only considered one method of change. Suppose, for instance, that the water found a natural means of escape—as, for instance, where this very bog sends a stream over the rocks into the Cliff Fields—it would not attack the clay bed at all, unless under some unusual pressure. Then suppose that when such pressure had come the water did not rise and top the clay bed, but that it found a small fissure part of the way down. Suppose there were several such reservoirs as I have mentioned—and from the formation of the ground I think it very likely, for in several places jutting rocks from either side come close together, and suggest a sort
