or as 5·33 : 1, say up to 3 feet, (an amplitude not probably reached by any earthquake that has ever occurred in historical time,) could it possibly produce earth fissures of even an inch wide by direct action, whether by stretching or otherwise.
The well-known Jamaica earth fissures, that were said to have opened and closed with the wave, and bit people in two, must be regarded as audacious fables; and having now examined a country precisely similar, in all important respects, with Calabria Ultra, I am satisfied, that both the engravings and the descriptions given, in the Historical Account by the Neapolitan Academy of the Earthquake of 1783, of the earth fissures therein produced, and designated constantly by the pompous term "voragines," are gross exaggerations, (as are many other parts of that narrative in other respects); and that many of the instances that they adduce, as "voragines," were really large landslips, the torn surfaces of whose planes of separation they thus name.
What has thus been in the preceding pages adduced as to the amplitude and velocity, of the greatest possible shock, points at once to the totally untenable nature, of the hypotheses upon which Messrs. Rogers, have proposed to account for the production of the great successive and parallel undulations, presented by a section transverse to the ranges, of the Appalachian chains.
Earth waves of such magnitude, or of anything at all like it, or resulting in such effects, are purely imaginary.
There is nothing in the facts the Neapolitan Academicians record, of fissures radiating to or from a central point incapable of explanation upon the principles above
