Page:The origin of continents and oceans - Wegener, tr. Skerl - 1924.djvu/210

184 yet little time is needed to show that it does not fit in with present-day knowledge. The ocean charts, incomplete as they are owing to the absence of soundings, show decisively that the connection is quite broken between the festoon and the main block.

If the movement of the continental block did not, as in Eastern Asia, occur at right angles to its margin, but parallel to it, the coastal chains could be stripped off by lateral displacements without the appearance of a window of sima between them and the main block. The basic principles are the same as for the similar phenomena which were illustrated for the interior of the continental blocks in, but mentally transferred to the continental margin. If the block moves towards the sima, then marginal folding occurs, and may be accompanied either by overfolds or thrusts or by echeloned folds, according to the direction or the movement. If it moves from the deep-sea floor, then the coastal chains will split off. But if the movement is a shearing one, then we have a fault with lateral displacement, and the marginal chain slides longitudinally. In this case also, the chain adheres to the solidified deep-sea floor. This process is especially well seen in the depth chart of the Drake Straits in, at the north end of Graham Land. Similarly the most southerly chain of the Sunda Islands (Sumba-Timor-Ceram-Buru), which has probably at one time formed the south-easterly continuation of the islands lying in front of Sumatra, has slipped past Java, until it was arrested by the advancing block of Australia-New Guinea.

California is another example. The Californian peninsula shows dragging phenomena on its lateral projections which appear to demonstrate a progressive impulse of the land-mass towards the south-east. The point of the peninsula is already thickened to