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CHAPTER V. 



Bahia Blanca — Geology — Extinct quadrupeds, four Edentata, horse, 

 ctenomys — Recent extinction — Longevity of species — Large animals do 

 not require luxuriant vegetation — Southern Africa — Siberian fossils — 

 Catalogue of extinct quadrupeds in South America — Two species of 

 Ostrich, habits of — Tinochorus — Oven-bird — Armadilloes — Venomous 

 snake, toad, lizard — Hybernation of animals — Habits of sea-pen — Indian 

 wars and massacres — Arrow-head, antiquarian relic. 



BAHIA BLANCA. 



The Beagle arrived on the 24th of August, and a week 

 afterwards sailed for the Plata. With Captain Fitzroy's 

 consent I was left behind, to travel by land to Buenos Ayres. 

 I will here add some observations, which were made during 

 this visit, and on a previous occasion, when the Beagle was 

 employed in surveying the harbour. Not much can be made 

 out respecting the geology. At the distance of some miles 

 inland, an escarpment of a great argillaceo-calcareous forma- 

 tion of rock extends. The space near the coast consists of 

 plains of hardened mud, and broad bands of sand-dunes, 

 which present appearances, that can easily be accounted for 

 by a rise of the land ; and of this phenomenon,* although to 

 a trifling amount, we have other proofs. 



At Punta Alta, a low cMff, about twenty feet high, exposes 

 a mass of partly consolidated shingle, irregularly interstrati- 

 fied with a reddish muddy clay, and containing numerous 

 recent shells. We may believe a similar accumulation 

 would now take place, on any point, where tides and waves 

 were opposed. In the gravel a considerable number of 

 bones were embedded. Mr. Owen, who has undertaken the 

 description of these remains, has not yet examined them 



• A few leagues further south, near the Bay of San Bias, M. D'Orbigny 

 found great beds of recent shells elevated between 25 and 30 feet above 

 the level of the sea.— Vol. ii., p. 43. 



