95 



CHAPTER V. 



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

 ctenomj^s — 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 visits 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 cliff, 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. 



