After having been twice driven back by heavy south-west gales, H.M.S. Beagle, a ten-gun brig, under the command of Captain Fitzroy, R.N., sailed from Devonport on December 27, 1831. The object of the expedition was to complete the survey of Patagonia and Tierra del Fuego, commenced under Captain King in 1826-30; to survey the shores of Chile, Peru, and of some of the islands in the Pacific; and to carry a chain of chronometrical measurements round the world.
On January 16, 1832, we touched at Porto Praya, St. Jago, in the Cape de Verde archipelago, and sailed thence to Rio de Janeiro, Brazil. Delight is a weak term to express the higher feelings of wonder, astonishment, and devotion which fill the mind of a naturalist in wandering through the Brazilian tropical forest. The noise from the insects is so loud that it may be heard at sea several hundred yards from the shore, yet within the recesses of the forest a universal silence seems to reign. The wonderful and beautiful flowering parasites invariably struck me as the most novel object in these grand scenes. Among the cabbage-palms, waving their elegant heads fifty feet from the ground, were woody creepers, two feet in circumference, themselves covered by other creepers.
The humming birds are fond of shady spots, and these little creatures, with their brilliant plumage, buzzing round the flowers with wings vibrating so rapidly as scarcely to be visible, seek the tiny insects in the calyx rather than the fabled honey. Insects are particularly numerous, the bees excepted. The Beagle was employed surveying the extreme southern and eastern coasts of America south of the Plata during the two succeeding years. The almost entire absence of trees in the pampas of Uruguay, the provinces of Buenos Ayres [now Argentina], and Patagonia is remarkable.
Fifteen miles from the Rio Negro, the principal river on the whole line of coast between the Strait of Magellan and the Plata, are several shallow lakes of brine in winter, which in summer are converted into fields of snow-white salt two and a half miles long and one broad. The border of the lakes is formed of mud, which is thrown up by a kind of worm. How surprising it is that any creature should be able to exist in brine, and that they should be crawling among crystals of sulphate of soda and lime!
The valley of the Rio Negro, broad as it is, has merely been excavated out of the sandstone plain; and everywhere the landscape wears the same sterile aspect.
II.—Fossil Monsters of the Pampas
The pampas are formed from the mud, gravel, and sand thrown up by the sea during the slow elevation of the land; and the section disclosed at Punta Alta, a few miles from Bahia Blanca, was interesting from the number and extraordinary character of the remains of gigantic land animals embedded in it. I also found remains of immense armadillo-like animals on the banks of a tributary of the Rio Negro; and, indeed, I believe that the whole area of the pampas is one wide sepulchre of these extinct colossal quadrupeds. The following, which I unearthed, are now deposited in the College of Surgeons, London.
(1) Head and bones of a megatherium, the huge dimensions of which are expressed by its name; (2) the megalonyx, a great allied animal; (3) the perfect skeleton of a scelidorium, also an allied animal, as large as a rhinoceros, in structure like the Cape ant-eater, but in some other respects approaching the armadilloes; (4) the mylodon Darwinii, a closely related genus, and little inferior in size; (5) another gigantic dental quadruped; (6) another large animal very like an armadillo; (7) an extinct kind of horse (it is a marvellous fact in the history of the mammalia that, in South America, a native horse should have lived and disappeared, to be succeeded in after ages by the countless herds descended from the few introduced with the Spanish colonists); (8) a pachydermatous animal, a huge beast with a long neck like a camel; (9) the toxodon, perhaps the strangest animal ever discovered; in size it equalled an elephant, or megatherium, but was intimately related to the Gnawers, the order which at the present day includes most of the smallest quadrupeds; and judging from the position of the eyes, ears, and nostrils, it was probably aquatic.
We have good evidence that these gigantic quadrupeds, more different from those of the present day than the oldest of the Tertiary quadrupeds of Europe, lived whilst the sea was peopled with most of its present inhabitants. These animals migrated on land, since submerged, near Behring's Strait, from Siberia into North America, and thence on land, since submerged, in the West Indies into South America, where they mingled with the forms characteristic of that southern continent, and have since become extinct.
The existing animals of the pampas include the puma, the South American lion, while the birds are numerous. The largest is the ostrich, which is found in groups. The ostriches are fleet in pace, prefer running against the wind, and freely take to the water. At first start they expand their wings, and, like a vessel, make all sail. Of mammalia, the jaguar, or South American tiger, is the most formidable. It frequents the wooded and reedy banks of the great rivers. There are four species of armadilloes, notable for their smooth, hard, defensive covering. Of reptiles there are many kinds. One snake, a trigonocephalus, has in some respects the structure of a viper with the habits of a rattlesnake. The expression of this snake's face is hideous and fierce. I do not think I ever saw anything more ugly, excepting, perhaps, some of the viper-bats.