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Show 272 PHYSIOGNOMY OF PLANTS. and Peru are washed by a cold current coming from the south and turning to the westward off Punta Parina, the temperature of which I found, in 1802, to be only 12°.5 Reaumur (60°.2 Fahr.), while the undisturbed adjacent masses of water were from 22° to 23° Reaumur (8!0.5 to 83°.8 Fahr.); and there are also among the Galapagos small currents running between the islands, having a temperature of only l1°.7 Reaumur (58°.2 Fahr.). But these lower temperatures do not extend farther to the north along the shores of the Pacific, and are not found upon the coasts of Guayaquil, Guatimala and Mexico; nor does a lower temperature prevail at the Cape de Verde Islands on the West Coast of Africa, or at the small islands of St. Paul (St. Paul's rocks), or at St. Helena, Ascension, or San Fernando N oronha-which yet are all without coral reefs. While this absence of coral reefs appears to characterize the weste? ·n coasts of Africa, America, and Australia, on the other hand such reefs abound on the eastern coasts of tropical America, of Africa, on the coasts of Zanzibar and Australia, and on that of New South Wales. The coral banks which I have chiefly had opportunities of observing are those of the interior of the Gulf of 1\lexico, and those to the south of the Island of Cuba, in what are called the "Gardens of the King and Queen" ( J ardines y J ardinillos del Rey y de la Reyna). It was Columbus himself who, on his second voyage, in May 1494, gave that name to this little group of islands, because the agreeable mixture of the silver-leaved arborescent Tournefortia gnapholoides, flowering species of Dolichos, A vicennia nitida, and mangrove hedges, gave to the coral islands the appearance of a group of floating gardens. "Son Cayos verdes y graciosos llenos de arboledas," says the Admiral. On the passage from Batabano to Trinidad de Cuba, I remained several days in these gardens, situated to the east of the larger island, called the Isla de Pinos, which is rich in mahogany trees: my stay was for the purpose of determining the longitude of the different keys (Cayos). The Cayo Flamenco, Cayo Bonito, Cayo de Diego Perez, and Cayo de Piedras, are coral islands rising only from eight to fourteen inches above the level of the sea. The upper edge of the reef does not consist simply of blocks of dead coral; it is rather a true conglomerate, in which angular pieces of coral, cemented together with grains of quartz, are embedded. In |