THE SUBMARINE COAL-MINES The next day, the 20th of February, I awoke very late: the fatigues of the previous night had prolonged my sleep until eleven o’clock. I dressed quickly, and hastened to find the course the Nautilus was taking. The instruments showed it to be still toward the south, with a speed of twenty miles an hour and a depth of fifty fathoms. The species of fishes here did not differ much from those already noticed. There were rays of giant size, five yards long, and endowed with great muscular strength, which enabled them to shoot above the waves; sharks of many kinds; amongst others, one fifteen feet long, with triangular sharp teeth, and whose transparency rendered it almost invisible in the water. Amongst bony fish Conseil noticed some about three yards long, armed at the upper jaw with a piercing sword; other bright-coloured creatures, known in the time of Aristotle by the name of the sea-dragon, which are dangerous to capture on account of the spikes on their back. About four o’clock, the soil, generally composed of a thick mud mixed with petrified wood, changed by degrees, and it became more stony, and seemed strewn with conglomerate and pieces of basalt, with a sprinkling of lava. I thought that a mountainous region was succeeding the long plains; and accordingly, after a few evolutions of the Nautilus, I saw the southerly horizon blocked by a high wall which seemed to close all exit.