"Our ship was over the epicentre,"[5] he says, "and was so severely shaken that at first the Admiral feared the complete destruction of the corvette." He then makes the statement that the shocks which were directly upwards were so strong as to throw heavy objects in the air; for example, a heavy gun and its carriage. While it is possible, as Dutton remarks, that this incident of the heavy gun and carriage was grossly exaggerated, yet it should not be forgotten that in the case of submarine eruptions such as that which resulted in the production of the island of Sabrina, an immense column of water, weighing probably many times more than a gun and its carriage, was observed to be shot high into the air. Where the seaquake is produced by a strong submarine volcanic eruption, there is a violent commotion of the water itself, so that a vessel passing over such a point may be greatly injured, and, indeed, even destroyed. Such disasters, however, are fortunately exceedingly rare. Among other common effects of seaquakes is the destruction of fish already mentioned by the sudden blow to the water stunning and killing them, just as the explosion of dynamite or other high explosives does in a lake or pond. The most marked effect, however, of seaquakes is the starting of the great wave on the coasts of continents and islands. There are certain parts of the ocean that are especially liable to seaquakes. Some of the more important of these, as shown by Rudolph's researches, are: The region already referred to in the narrowest parts of the Atlantic Ocean between Africa and South America almost immediately under the equator. Here there are two well marked regions. One is in lat. 1° N., long. 30° W., where there is a submarine ridge, the tops of which form what are known as St. Paul's Rock. The ocean here is very deep, the slopes of the ridge descending rapidly. It is on these slopes that earthquakes are very apt to occur just as they do on the steep slopes of mountain ranges. The other region, called by Rudolph the _Equatorial District_, lies a little further to the east on both sides of the equator in long. 20° W. It appears from Rudolph's researches that between 1845 and 1893 no less than thirty-seven seaquakes were reported in the logs of ships in the neighborhood of St. Paul's Rock, and between 1747 and 1890, in the equatorial district, there were forty-nine seaquakes. It must not be supposed, however, that these were all the quakes in the regions during these times, since, of course, many shocks must have happened that were not felt even by vessels in the neighborhood and many more, when this portion of the ocean was free from any craft. In the North Atlantic there is a portion of the ocean's bed known as the _West Indies Deep_. Here the bed is marked by great depths and by many irregularities and is, therefore, a region where seaquakes are common.