G. W. VON ZAHN. Die zerstörende Arbeit des Meeres an Steilküsten nach Beobachtungen in der Bretagne und Normandie in den Jahren 1907 und 1908, Mitt. d. Geogr. Ges. Hamb., vol. 24, 1910, pp. 193-284, pls. 12-27. CHAPTER XIX COAST RECORDS OF THE RISE OR FALL OF THE LAND =The characters in which the record has been preserved.=—The peculiar forms into which the sea has etched and molded its shores have been considered in the last chapter. Of these the more significant are the notched rock cliff, the cut rock terrace, the sea cave, the sea arch, the stack, and the sloping cliff and terrace, among the carved features; and the barrier beach and built terrace, among the molded forms. It is important to remember that the molded forms, by the very manner of their formation, stand in a definite relationship to the carved features; so that when either one has been in part effaced and made difficult of determination, the discovery of the other in its correct natural position may remove all doubt as to the origin of the relic. [Illustration: FIG. 270.—The east coast of Florida, with shore line characteristic of a raised coast.] In studies of the change of level of the land, it is customary to refer all variations to the sea level as a zero plane of reference. It is not on this account necessary to assume that the changes measured from this arbitrary datum plane are the absolute upward or downward oscillations which would be measured from the earth’s center; for the sea, like the land, has been subject to its changes of level. There need, however, be no apology for the use of the sea surface as a plane of reference; for it is all that we have available for the purpose, and the changes in level, even if relative only, are of the greatest significance. It is probable that in most cases where the coast line is rising from uplift, some portion of the sea basin not far distant is becoming deepened, so that the visible change of level is the algebraic sum of the two effects. =Even coast line the mark of uplift.=—It was early pointed out in this volume (p. 158) that the floor of the sea in the neighborhood of the land presents a relatively even surface. The carving by waves, combined with the process of deposition of sediments, tends to fill up the minor irregularities of surface and preserve only the features of larger scale, and these in much softened outlines. Upon the continents, on the contrary, the running water, taking advantage of every slight difference in elevation and searching out the hidden structure planes within the rock, soon etches out a surface of the most intricate detail. The effect of elevation of the sea floor into the light of day will therefore be to produce an even shore line devoid of harbors (Fig. 270). If the coast has risen along visible planes of faulting near the sea margin, the coast line, in addition to being even, will usually be made up of notably straight elements joined to one another. [Illustration: