Читать книгу Legendary Islands of the Atlantic: A Study of Medieval Geography онлайн

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It will be observed that the whole of this very tempting edifice is built on the declared impossibility of tachylyte forming on the sea bottom under heavy water pressure. But Professor Schuchert insists that: “It is not pressure so much as it is a quick loss of temperature that brings about the vitreous structure in lava. In other words, vitreous lava apparently can be formed as well in the ocean depths as on the lands. What the cable layers got was probably the superficial glassy crust of probable subterranean lava flows.”28 If that be so, there is, of course, no need to infer a descent of territory into the depths in that region of the mid-Atlantic. This tachylyte matter seems enveloped in uncertainty.

On the other hand, it is well known that volcanic outbursts and earthquakes have been rather frequent and alarming even in modern times among the islands of the eastern Atlantic archipelagoes, especially the Canaries and the lowest and middle groups of the Azores. In some instances the nearest mainland also has suffered, as notably on “Lisbon-earthquake day,” and the various occasions of disturbances cited by Navarro. Also, there is the memorable instance of a small island that was thrust upward from the depths before the eyes of a British naval ship’s crew and remained in sight for several days. Changes of a distinctly non-volcanic character have also occurred, as when an appreciable slice of cliff wall broke away from Flores and sank, raising a great wave which did damage, with loss of life on Corvo, some nine miles away. Moreover, Corvo was once considerably larger than it is now in comparison with this neighbor, Flores (or Li Conigi), if we may trust to the general testimony of fourteenth-century and fifteenth-century maps. But all these shiftings and transformations for a long time past have been local and usually rather narrowly restricted. It does not follow that no depressions or elevations of greater extent have suddenly occurred in times before men regularly made permanent records; yet it must be owned that the belief in any very large sunken Atlantis derives no direct support from what we actually know of volcanic and seismic action in that region in historic centuries.