200 PATAGONIA. Jan. 1834. 



Roy on a long walk round the head of the harbour. We 

 were eleven hours without tasting any water, and some of 

 the party were quite exhausted. From the summit of a hill 

 (since well named Thirsty Hill) a fine lake was spied, and two 

 of the party proceeded with concerted signals to show whether 

 it was fresh water. What was our disappointment to find a 

 snow-white expanse of salt, crystallized in great cubes ! We 

 attributed our extreme thirst to the dryness of the atmo- 

 sphere ; but whatever the cause might be, we were exceed- 

 ingly glad late in the evening to get back to the boats. 

 Although we could nowhere find, during our whole visit, a 

 single drop of fresh water, yet some must exist ; for by an odd 

 chance I found on the surface of the salt water, near the head 

 of the bay, a Colymbetes not quite dead, which in all probabi- 

 lity had lived in some not far distant pool. Three other kinds 

 of insects, — a Cincindela, like hybrida, Cymindis, and a Har- 

 palus, which all Hve on muddy flats occasionally overflowed by 

 the sea, and one other beetle found dead on the plain, — com- 

 pletes the list of coleoptera. A good-sized fly (Tabanus) Avas 

 extremely numerous, and tormented us by its painful bite. 

 The common horsefly, which is so troublesome in the shady 

 lanes of England, belongs to this genus. We here have the 

 puzzle, that so frequently occurs in the case of musquitoes ; 

 on the blood of what animals do these insects commonly 

 feed ? The guanaco is nearly the only warmblooded quadru- 

 ped, and they are present in numbers quite inconsiderable, 

 compared to the multitude of flies. 



The foundation of porphyry is not here present, as it was at 

 Port Desire, and in consequence the tertiary deposits are ar- 

 ranged with greater regularity. Five successive plains of dif- 

 ferent altitudes are very distinct. The lower one is a mere 

 fringe nearly on a level with the sea, but the upper one is 

 elevated 950 feet. This latter is represented in this neighbovir- 

 hood only by a few truncate conical hiUs, of exactly the same 

 height. It was very interesting to stand on one of these flat 

 patches of gravel, and viewing the wide surrounding country, 

 to speculate on the enormous quantity of matter which must 



