CHAPTER V. 



Bahia Blanca 



Bahia Blanca — Geology — Numerous gigantic Quadrupeds — Recent 

 Extinction — Longevity of Species — Large Animals do not require a 

 luxuriant vegetation — Southern Africa — Siberian Fossils — Two 

 Species of Ostrich — Habits of Oven-bird— Armadilloes — Venomous 

 Snake, Toad, Lizard— Hybernation of Animals— Habits of Sea- 

 Pen — Indian Wars and Massacres — Arrow-head, antiquarian Relic. 



THE Beagle arrived here on the 24th of August, and a 

 week afterwards sailed for the Plata. With Captain 

 Fitz Roy'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. 



The plain, at the distance of a few miles from the coast, 

 belongs to the great Pampean formation, which consists in 

 part of a reddish clay, and in part of a highly calcareous 

 marly rock. Nearer the coast there are some plains formed 

 from the wreck of the upper plain, and from mud, gravel, 

 and sand thrown up by the sea during the slow elevation of 

 the land, of which elevation we have evidence in upraised 

 beds of recent shells, and in rounded pebbles of pumice scat- 

 tered over the country. At Punta Alta we have a section oi 

 one of these later-formed little plains, which is highly inter- 

 esting from the number and extraordinary character of the 

 remains of gigantic land-animals embedded in it. These have 

 been fully described by Professor Owen, in the Zoology of the 

 voyage of the Beagle, and are deposited in the College of Sur- 

 geons. I will here give only a brief outline of their nature. 



First, parts of three heads and other bones of the Mega- 

 therium, the huge dimensions of which are expressed by its 

 name. Secondly, the Megalonyx, a great allied animal. 

 Thirdly, the Scelidotherium, also an allied animal, of which 

 I obtained a nearly perfect skeleton. It must have been as 



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