Geography. Strabo

of Hercules, and thus, much that was formerly covered by water, had been left dry.318 He gives as the cause of this, that anciently the levels of the Mediterranean and Atlantic were not the same, and states that a bank of earth, the remains of the ancient separation of the two seas, is still stretched under water from Europe to Africa. He adds, that the Euxine is the most shallow, and the seas of Crete, Sicily, and Sardinia much deeper, which is occasioned by the number of large rivers flowing into the Euxine both from the north and east, and so filling it up with mud, whilst the others preserve their depth. This is the cause of the remarkable sweetness of the Euxine Sea, and of the currents which regularly set towards the deepest part. He gives it as his opinion, that should the rivers continue to flow in the same direction, the Euxine will in time be filled up [by the deposits], since already the left side of the sea is little else than shallows, as also Salmydessus,319 and the shoals at the mouth of the Ister, and the desert of Scythia,320 which the sailors call the Breasts. Probably too the temple of Ammon was originally close to the sea, though now, by the continual deposit of the waters, it is quite inland: and he conjectures that it was owing to its being so near the sea that it became so celebrated and illustrious, and that it never would have enjoyed the credit it now possesses had it always been equally remote from the sea. Egypt too [he says] was formerly covered by sea as far as the marshes near Pelusium,321 Mount Casius,322 and the Lake Sirbonis.323 Even at the present time, when salt is being dug in Egypt, the beds are found under layers of sand and mingled with fossil shells, as if this district had formerly been under water, and as if the whole region about Casium and Gerrha324 had been shallows reaching to the Arabian Gulf. The sea afterwards receding left the land uncovered, and the Lake Sirbonis remained, which having afterwards forced itself a passage, became a marsh. In like manner the borders of the Lake Mœris resemble a sea-beach rather than the banks of a river. Every one will admit that formerly at various periods a great portion of the mainland has been covered and again left bare by the sea. Likewise that the land now covered by the sea is not all on the same level, any more than that whereon we dwell; which is now uncovered and has experienced so many changes, as Eratosthenes has observed. Consequently in the reasoning of Xanthus there does not appear to be any thing out of place.

      5. In regard to Strato, however, we must remark that, leaving out of the question the many arguments he has properly stated, some of those which he has brought forward are quite inadmissible. For first he is inaccurate in stating that the beds of the interior and the exterior seas have not the same level, and that the depth of those two seas is different: whereas the cause why the sea is at one time raised, at another depressed, that it inundates certain places and again retreats, is not that the beds have different levels, some higher and some lower, but simply this, that the same beds are at one time raised, at another depressed, causing the sea to rise or subside with them; for having risen they cause an inundation, and when they subside the waters return to their former places. For if it is so, an inundation will of course accompany every sudden increase of the waters of the sea, [as in the spring-tides,] or the periodical swelling of rivers, in the one instance the waters being brought together from distant parts of the ocean, in the other, their volume being increased. But the risings of rivers are not violent and sudden, nor do the tides continue any length of time, nor occur irregularly; nor yet along the coasts of our sea do they cause inundations, nor any where else. Consequently we must seek for an explanation of the cause either in the stratum composing the bed of the sea, or in that which is overflowed; we prefer to look for it in the former, since by reason of its humidity it is more liable to shiftings and sudden changes of position, and we shall find that in these matters the wind is the great agent after all. But, I repeat it, the immediate cause of these phenomena, is not in the fact of one part of the bed of the ocean being higher or lower than another, but in the upheaving or depression of the strata on which the waters rest. Strato’s hypothesis evidently originated in the belief that that which occurs in rivers is also the case in regard to the sea; viz. that there is a flow of water from the higher places. Otherwise he would not have attempted to account for the current he observed at the Strait of Byzantium in the manner he does, attributing it to the bed of the Euxine being higher than that of the Propontis and adjoining ocean, and even attempting to explain the cause thereof: viz. that the bed of the Euxine is filled up and choked by the deposit of the rivers which flow into it; and its waters in consequence driven out into the neighbouring sea. The same theory he would apply in respect to the Mediterranean and Atlantic, alleging that the bed of the former is higher than that of the latter in consequence of the number of rivers which flow into it, and the alluvium they carry along with them. In that case there ought to be a like influx at the Pillars and Calpe,325 as there is at Byzantium. But I waive this objection, as it might be asserted that the influx was the same in both places, but owing to the interference of the ebb and flow of the sea, became imperceptible.

      6. I rather make this inquiry:—If there were any reason why, before the outlet was opened at Byzantium, the bed of the Euxine (being deeper than either that of the Propontis326 or of the adjoining sea327) should not gradually have become more shallow by the deposit of the rivers which flow into it, allowing it formerly either to have been a sea, or merely a vast lake greater than the Palus Mæotis? This proposition being conceded, I would next ask, whether before this the bed of the Euxine would not have been brought to the same level as the Propontis, and in that case, the pressure being counter-poised, the overflowing of the water have been thus avoided; and if after the Euxine had been filled up, the superfluous waters would not naturally have forced a passage and flowed off, and by their commingling and power have caused the Euxine and Propontis to flow into each other, and thus become one sea? no matter, as I said above, whether formerly it were a sea or a lake, though latterly certainly a sea. This also being conceded, they must allow that the present efflux depends neither upon the elevation nor the inclination of the bed, as Strato’s theory would have us consider it.

      7. We would apply the same arguments to the whole of the Mediterranean and Atlantic, and account for the efflux of the former, not by any [supposed] difference between the elevation and inclination of its bed and of that of the Atlantic, but attribute it to the number of rivers which empty themselves into it. Since, according to this supposition, it is not incredible that had the whole of the Mediterranean Sea in times past been but a lake filled by the rivers, and having overflowed, it might have broken through the Strait at the Pillars, as through a cataract; and still continuing to swell more and more, the Atlantic in course of time would have become confluent by that channel, and have run into one level, the Mediterranean thus becoming a sea. In fine, the Physician did wrong in comparing the sea to rivers, for the latter are borne down as a descending stream, but the sea always maintains its level. The currents of straits depend upon other causes, not upon the accumulation of earth formed by the alluvial deposit from rivers, filling up the bed of the sea. This accumulation only goes on at the mouths of rivers. Such are what are called the Stethe or Breasts at the mouth of the Ister,328 the desert of the Scythians, and Salmydessus, which are partially occasioned by other winter-torrents as well; witness the sandy, low, and even coast of Colchis,329 at the mouth of the Phasis,330 the whole of the coast of Themiscyra,331 named the plain of the Amazons, near the mouths of the Thermodon332 and Iris,333 and the greater part of Sidene.334 It is the same with other rivers, they all resemble the Nile in forming an alluvial deposit at their mouths, some more, some less than others. Those rivers which carry but little soil with them deposit least, while others, which traverse an extended and soft country, and receive many torrents in their course, deposit the greatest quantity. Such for example is the river Pyramus,335 by which Cilicia has been considerably augmented, and concerning which an oracle has declared, “This shall occur when the wide waters of the Pyramus have enlarged their banks as far as sacred Cyprus.”336 This river becomes navigable from the middle of the plains of Cataonia, and entering Cilicia337 by the defiles of the Taurus, discharges itself into the sea which flows between that country and the island of Cyprus.

       8. These river deposits are prevented from advancing further into the sea by the regularity of the ebb and flow, which continually drive them back. For after the manner of living creatures, which go on inhaling and exhaling their breath continually, so the sea in a like way keeps up a constant motion in and out of itself. Any one may observe who stands on the sea-shore when the waves are in motion, the regularity with which they cover, then leave bare, and then again cover up his feet. This agitation of the sea produces a continual movement on its surface, which even when it is most tranquil has considerable