"This," said Simon, "is one of the greatest facts in history!"
"It's the greatest, my son. Since the world has been a world and since men have been gathered into nations, there has been no physical phenomenon of greater importance than this. And to think that I predicted the whole thing, the causes and the effects, the causes which I am the only one to know!"
"And what are they?" asked Simon. "How is it that I was able to pass? How is it. . . ."
Old Sandstone checked him with a gesture which reminded Simon of the way in which his former lecturer used to begin his explanations at college; and the old codger, taking a pen and a sheet of paper, proceeded:
"Do you know what a fault is? Of course not! Or a horst? Ditto! Oh, a geology-lesson at Dieppe college was so many hours wasted! Well, lend me your ears, young Dubosc! I will be brief and to the point. The terrestrial rind—that is, the crust which surrounds the internal fire-ball, of solidified elements and eruptive or sedimentary rocks—consists throughout of layers superposed like the pages of a book. Imagine forces of some kind, acting laterally, to compress those layers. There will be corrugations, sometimes actual fractures, the two sides of which, sliding one against the other, will be either raised or depressed. Faults is the name which we give to the fractures that penetrate the terrestrial shell and separate two masses of rock, one of which slides over the plane of fracture. The fault, therefore, reveals an edge, a lower lip produced by the subsidence of the soil, and an upper lip produced by an elevation. Now it happens that suddenly, after thousands and thousands of years, this upper lip, under the action of irresistible tangential forces, will rise, shoot upwards, and form considerable outthrows, to which we give the name of horsts. This is what has just taken place. . . . There exists in France, marked on the geological charts, a fault known as the Rouen fault, which is an important dislocation of the Paris basin. Parallel to the corrugations of the soil, which have wrinkled the cretaceous and tertiary deposits in this region from north-east to north-west, it runs from Versailles to seventy-five miles beyond Rouen. At Maromme, we lose it. But I, Simon, have found it again in the quarries above Longueville and also not far from Dieppe. And lastly I have found it . . . where do you think? In England, at Eastbourne, between Hastings and Newhaven! Same composition, same disposition. There was no question of a mistake. It ran from France to England! It ran under the Channel. . . . Ah, how I have studied it, my fault, Old Sandstone's fault, as I used to call it! How I have sounded it, deciphered its meanings, questioned it, analysed it! And then, suddenly in 1912, some seismic shocks affected the table-lands of the Seine-Inférieure and the Somme and acted in an abnormal manner as I was able to prove—on the tides! Shocks in Normandy! In the Somme! Right out at sea! Do you grasp the strangeness of such a phenomenon and how, on the other hand, it acquired a significant value from the very fact that it took place along a fault? Might we not suppose that there were stresses along this fault, that captive forces were seeking to escape through the earth's crust and attacking the points of least resistance, which happened to lie precisely along the lines of the faults? . . . You may call it an improbable theory. Perhaps so; but at any rate it seemed worth verifying. And I did verify it. I made diving-experiments within sight of the French coast. At my fourth descent, in the Ridin de Dieppe, where the depth is only thirty feet, I discovered traces of an eruption in the two blocks of a fault all of whose elements tallied with those of the Anglo-Norman fault . . . That was all I wanted to know. There was nothing more to do but wait . . . a century or two . . . or else a few hours. . . . Meanwhile it was patent to me that sooner or later the fragile obstacle opposed to the internal energies would break down and the great upheaval would come to pass. It has come to pass."
Simon listened with growing interest. Old Sandstone illustrated his lecture with diagrams drawn with broad strokes of the pen and smeared with blots which his sleeve or fingers generously spread all over the paper. Drops of sweat also played their part, falling from his forehead, for Old Sandstone was always given to perspiring copiously.
He repeated:
"It has come to pass, with a whole train of precursory or concomitant phenomena: submarine eruptions, whirlpools, boats and ships hurled into the air and drawn under by the most terrible suction; and then seismic tremors, more or less marked, cyclones, waterspouts and the devil's own mischief; and then a cataclysm of an earthquake. And immediately afterwards, indeed at the same moment, the shooting up of one lip of the fault, projecting from one coast to the other, over a width of seventy or eighty miles. And then, on the top of it, you, Simon Dubosc, crossing the Channel at a stride. And this perhaps was not the least remarkable fact, my boy, in the whole story."
Simon was silent for some time. Then he said:
"So far, so good. You have explained the emergence of the narrow belt of earth which I walked along and whose width I measured with my eyes, I might say, incessantly. But how do you explain the emergence of this immense region which now fills the Straits of Dover and part of the Channel?"