90 GEOLOGY. [chap. v. 



the smell can be perceived at a league distant ; more than 

 once, when entering the harbour of Monte Video, the wind 

 being off shore, we have perceived the odour on board the 

 Beagle. Certain it is, that every animal most willingly 

 makes room for the Zorillo. 



CHAPTER V 



BAHIA BLANCA. 



Bahia Blanca — Geology — Numerous gigantic extinct Quadru- 

 peds — 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 — Indians' 

 Wars and Massacres — Arrow-head, Antiquarian Relic. 



The Beagle arrived hei"e 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 scattered 

 over the country. At Punta Alta we have a section of one 

 of these later-formed little plains, which is highly interesting 

 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 

 Surgeons. I will here give only a brief outline of their 

 nature. 



First, parts of three heads and other bones of the 

 Megatherium, the huge dimensions of which are expressed 

 by its name. Secondly, the Megalonyx, a great allied 



