Page:Popular Science Monthly Volume 43.djvu/263

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251
THE BAY OF FUNDY TIDES AND MARSHES.

haustless fertility? These are questions often asked by tourists, and which are answered, imperfectly no doubt, in the following pages.

North, of Cape Cod the continental coast line recedes abruptly westward, and then sweeps in a long curve northeastwardly till the head waters of the Bay of Fundy are reached. Turning again on itself, its course is westward to Cape Sable, from which it again stretches away toward the east as the southern shore of Nova Scotia. Thus, between Capes Cod and Sable lies the long, narrow, open Bay of Maine, which terminates toward the north and east in the landlocked Bay of Fundy. In the shallow waters of this larger open bay the tidal impulse, which over ocean depths moves only as a wave of vertical oscillation, is changed into one of translation. As the effect of this transformation the whole body of water moves first landward, and then, sweeping round with the curving coast line, skirts the southern shores of Maine and New Brunswick, till it reaches the narrow strait between Briar Island and Grand Manan. Compressed between these closer limits the water is forced onward with increasing velocity into the Bay of Fundy. Part finds its way into the Annapolis Basin and its tributary rivers, while the main current moves onward till it meets the tongue of land which terminates in Cape d'Or. Here it divides, the northern portion filling Shepody and Cumberland Basins; while the southern half rushes onward through the narrow entrance to the Basin of Minas. As it passes Cape Blomidon this swirling, eddying, foaming torrent reaches its greatest velocity—a rate of ten or twelve miles an hour.

Thus it is that the long, sickle-curved Maine coast gradually gathers up the water rolled upon it twice a day by the rhythmic ocean movements, and, throwing it backward, presses it at last into the funnel-shaped Bay of Fundy and its adjacent basins, covering with a semi-daily flood the low and unprotected marshlined shores and filling the channels of the tributary rivers for many miles inland to a height of ten, twenty, or thirty feet above their fresh-water levels. Such, in a general way, is the set of conditions under which the spectacular and physiographical effects of ordinary tidal phenomena are exaggerated in the Fundy tides far beyond their normal limits. At some points the extreme elevation of the flood tide above low-water mark is as great as seventy feet. In some of the rivers, particularly in the Peticodiac of New Brunswick and in the Shubenacadie of Nova Scotia, the upward flow against the fresh-water current forms a rapidly moving wall or bore several feet in height, the rushing sound of which can be heard at a considerable distance, while in others the two currents meet and mingle so quietly that an observer can hardly tell where the backward flow begins.