The consumption of guano in Western Europe, and particularly in England, increases with surprising rapidity. On the island of Iquique a layer thirty feet deep, and covering a space of 220,000 square feet, has been entirely removed within twenty-seven years. In the year 1854, 250,000 tons were dug in the Chincha Islands, and the actual annual exportation amounts to double the quantity. The digestive functions of the Sula and her companions thus bring in _larger_ sums to the Peruvian Government than all the silver mines of Cerro de Pasco, and the transport of the guano employs larger fleets than ever Spain possessed at the brightest period of her power. "The Chincha Islands," says Castelnau (_Expédition dans les Parties Centrales de l'Amérique du Sud_; Paris, 1851), "are completely desert and devoid of vegetation; their granite soil is clearly distinguished by its colour from the thick stratum of guano with which it is covered, and the surface of which looks at a distance like snow. The steep banks render landing difficult, but facilitate at the same time the shipping of the produce, as the vessels lie at anchor close to the pits. Digging takes place at three places, close to one another, and the traveller has only to compare the enormous deposits with the smallness of the excavations, which at some distance are hardly perceptible, to convince himself of the inexhaustible supply. Some huts have been constructed on the island, where, in the midst of ammoniacal effluvia, some Peruvian customhouse officers and soldiers superintend the working of the guano-mines." [Illustration: Birds of Passage.] CHAP. XI. THE REPTILES OF THE OCEAN. The Saurians of the Past Seas.--The Anatomical Structure of the Turtles.--Their Size.--Their Visits to the Shores.--The Dangers that await their Young.--Turtles on the Brazilian Coast.--Prince Maximilian of Neuwied and the Turtle.--Conflicts of the Turtles with Wild Dogs and Tigers on the Coast of Java.--Turtle-catching on Ascension Island.--Tortoise-shell.--The Amblyrhynchus cristatus.--Marine Snakes.--The Great Sea-Snake. There was a time when the reptiles were the monarchs of the sea, when the ocean swarmed with gigantic saurians, tyrants of the fishes, combining the swiftness of the dolphin with the rapacity of the crocodile. Had those monsters of the deep been endowed with human intelligence, they would most likely also, with human arrogance, have boasted of an eternal sway. For where in the whole ocean was the enemy that could cope with them? Did not all beings flee wherever they appeared? and did not the inexhaustible sea promise them an everlasting supply of food? [Illustration: Ichthyosaurus.] But in spite of their colossal power, the saurians, like all created beings, have been forced to succumb to time.