the requisite horizontal contraction in the folded mountain chains; in fact, it makes this possible for the first time. For if the earth as a whole does not diminish to the same amount as its crust is compressed, then every compression of the crust corresponds to a rift at another place, and we thus arrive of necessity at the idea that the outermost skin of rocks no longer clothes the whole world. In addition, the continental masses, with their contrast to the extensive oceanic areas, certainly do not lend themselves to any other explanations. The theory of the displacement of continents thus replaces the contraction theory, which must be completely rejected.
Further, a separate explanation is also needed with reference to the doctrine of the sunken bridging-continents and the already mentioned contrary doctrine of the permanence of the oceans. The relation of the displacement theory to both these doctrines is different from that to the contraction theory. To anticipate the results. The arguments which are led out into battle by both these doctrines are correct, and so therefore are their mutual refutations. Each is based on only that portion of the facts necessary for a favourable judgment and receives its refutation directly the other portion is introduced. The displacement theory will fit the entire facts, and therefore prepares the way for a reconciliation of these hostile doctrines in a manner which satisfies all reasonable demands of both parties. In order to do this we must go further into the subject.
The advocates of the bridging-continents rely on the nowadays well-established fact that the close affinities of fauna and flora of widely separated continents require extensive land connections in the past. The ever-increasing stream of separate discoveries allows the picture of these connections to grow under our eyes, and to-day a very far-reaching agreement
