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. RELATION OF THE SUBMARINE BANKS OF THE NORTH ATLANTIC TO THE PROBLEM There remain to be considered a small array of undersurface insular items which seem germane to our inquiry. Sir John Murray tells us that: Another remarkable feature of the North Atlantic is the series of submerged cones or oceanic shoals made known off the northwest coast of Africa between the Canary Islands and the Spanish peninsula, of which we may mention: the “Coral Patch” in lat. 34° 57′ N., long. 11° 57′ W., covered by 302 fathoms; the “Dacia Bank” in lat. 31° 9′ N., long. 13° 34′ W., covered by 47 fathoms; the “Seine Bank” in lat. 33° 47′ N., long. 14° 1′ W., covered by 81 fathoms; the “Concepcion Bank” in lat. 30° N. and long. 13° W., covered by 88 fathoms; the “Josephine Bank” in lat. 37° N., long. 14° W., covered by 82 fathoms; the “Gettysburg Bank” in lat. 36° N., long. 12 W., covered by 34 fathoms.[29]