From all of which we see that the Eastern hemisphere's crescent hollow--of which,I take it,the Mediterranean,Black,and Caspian Sea depressions are the remains--has been gradually filled in,by the elevation of the sea's bottom,and the extension of deltas from the detrital matter brought from the high interior of the continents by the rivers,or by the combined action of the two.Now,since the Gulf of Mexico has been constantly growing smaller,and the Mediterranean is being invaded by the land,I reason that similar causes will produce like effects here,and give to each continent an area far greater than our entire globe.The stormy ocean we behold in the west,which corresponds to our Atlantic,though it is far more of a mare clausum in the geographical sense,is also destined to become a calm and placid inland sea.There are,of course,modifications of and checks to the laws tending to increase the land area.England was formerly joined to the continent,the land connecting the two having been rather washed away by the waves and great tides than by any sinking of the English Channel's bottom,the whole of which is comparatively shallow.
Another case of this kind is seen in Cape Cod and the islands of Martha's Vineyard and Nantucket,all of which are washing away so rapidly that they would probably disappear before the next Glacial period,were we not engaged in preventing its recurrence.
These detached islands and sand-bars once formed one large island,which at a still earlier time undoubtedly was joined to the mainland.The sands forming the detached masses are in a great processional march towards the equator,but it is the result simply of winds and waves,there being no indication of subsidence.Along the coast of New Jersey we see denudation and sinking going on together,the well-known SUNKEN FOREST being an instance of the latter.The border of the continent proper also extends many miles under the ocean before reaching the edge of the Atlantic basin.Volcanic eruptions sometimes demolish parts of headlands and islands,though these recompense us in the amount of material brought to the surface,and in the increased distance they enable water to penetrate by relieving the interior of part of its heat,for any land they may destroy."CHAPTER XI.
A JOVIAN NIAGARA.
Four days later,after crossing a ridge of mountains that the pressure on the aneroid barometer showed to be about thirty-two thousand feet high,and a stretch of flat country a few miles in width,they came to a great arm of the sea.It was about thirty miles wide at its mouth,which was narrowed like the neck of a bottle,and farther inland was over one hundred miles across,and though their glasses,the clear air,and the planet's size enabled them to see nearly five hundred miles,they could not find its end.In the shallow water along its shores,and on the islands rising but a few feet above the waves,they saw all kinds of amphibians and sea-monsters.Many of these were almost the exact reproduction in life of the giant plesiosaurs,dinosaurs,and elasmosaurs,whose remains are preserved in the museums on earth.The reptilian bodies of the elasmosaurs,seventy-five feet in length,with the forked tongues,distended jaws and fangs of a snake,were easily taken for the often described but probably mythical sea-serpent,as partially coiled they occasionally raised their heads twelve or fifteen feet.
"Man in his natural state,"said Cortlandt,"would have but small chance of surviving long among such neighbours.Buckland,Ithink,once indulged in the jeu d'esprit of supposing an ichthyosaur lecturing on the human skull.'You will at once perceive,'said the lecturer,'that the skull before us belonged to one of the lower order of animals.The teeth are very insignificant,the power of the jaws trifling,and altogether it seems wonderful how the creature could have procured food.'
Armed with modern weapons,and in this machine,we are,of course,superior to the most powerful monster;but it is not likely that,had man been so surrounded during the whole of his evolution,he could have reached his present plane."Notwithstanding the striking similarity of these creatures to their terrestrial counterparts that existed on earth during its corresponding period,there were some interesting modifications.
The organs of locomotion in the amphibians were more developed,while the eyes of all were larger,the former being of course necessitated by the power of gravity,and the latter by the greater distance from the sun.
