The sea and the rivers change in many places, but it is not evident that it happens until after many centuries. In this manner does that change come about: as the waters break the hills, the earth of the hills falls to the bottom of the waters, and fills up the place of the water, and since the waters are forced out of their own position, they must occupy some other place where they can get room. By reason of that the sea washes over and submerges cities, towns and districts in which are the abodes of men in valleys and low
p.146places near the sea. The moisture57 that comes from the clouds is the cause of this, because when it falls, it flows constantly about the earth rooting up the soil, and everything insoluble and non-resistant that it finds in the earth it carries from place to place in the rivers, and the force of the rivers carries off the same things to the sea, and the bottom of the sea is filled with them58. On that account must the sea vacate that spot and seek some other. The hills break the place whither they go, and fill the valleys, therefore the dwelling places and domains of men change, i.e., cities, lands, hills and valleys.
For it is a natural thing for water, since it is fluid, not to be always in one place, but to travel from place to place. Consequently, the rivers carry the weakest soil with them to the sea, and from being a very long time there it becomes firm and hardens and becomes petrified,59 and from the constant beating of the waves beneath it and above it, the stones are carved and polished and assume different shapes. Some of them become round, some broad, some long and some short. Likewise the rivers bring, the sand and light stones to the sea, and they are gathered together by the beating to and fro of the waves outside, and after many hundreds of years it i.e., the new earth, formed as described mounts and rises up over the sea, and hills and mountains are formed from it,60 and the sea sends some of it towards other lands, and that is the material from which cities and lands are formed.
As a proof that it is true, there are to be seen in many places that have been submerged, stone houses, castles, churches and carved stones and planks, and many unquestionable signs from which it is proved that human habitations were some time in those places.
Another fact to prove the same thing; there will be found plainly in the summits of the hills and mountains, the paths and roads of the sea, which resembles the ridges and the small irregular furrows that are seen in the mud of the sea when the tide has ebbed. Also there are found many shells and small sea fish in the same places which have become hard, firm and petrified.61 In the same manner the rain forms the mountains and valleys of the world, because, when the rain flows into a place where it finds the soil weak, it turns it up and forms a furrow in it, and the edge of the furrow, on either side falls, both sand and soil, into the channel by the strength of the water and the water brings that with it to the rivers, and the rivers carry it to the sea, and from the excess of rain over a very long period ever falling into those furrows and constantly carrying away the soil and sand, those furrows become valleys of the sea, and at last the earth is left in hills and large mountains between them; and thus did the blessed Creator of the world order that.