1833.] R. NEGRO TO R. COLORADO. G7 



on infusoria or confervae. Thus we have a little living world 

 within itself, adapted to these inland lakes of brine. A minute 

 crustaceous animal (Cancer salinus) is said * to live in countless 

 numbers in the brine-pans at Lymington ; but only in those in 

 which the fluid has attained, from evaporation, considerable 

 strength — namely, about a quarter of a pound of salt to a pint of 

 water. Well may we affirm, that every part of the world is 

 habitable ! Whether lakes of brine, or those subterranean ones 

 hidden beneath volcanic mountains — warm mineral springs — the 

 wide expanse and depths of the ocean — the upper regions of the 

 atmosphere, and even the surface of perpetual snow — all support 

 organic beings. 



To the northM^ard of the Rio Negro, between it and the inha- 

 bited country near Buenos Ayres, the Spaniards have only one 

 small settlement, recently established at Bahia Blanca. The dis- 

 tance in a straight line to Buenos Ayres is very nearly five hun- 

 dred British miles. The \vandering tribes of horse Indians, 

 which have always occupied the greater part of this country, 

 having of late much harassed the outlying estancias, the govern- 

 ment at Buenos Ayres equipped some time since an army under 

 the command of General Rosas for the purpose of exterminating 

 them. The troops were now encamped on the banks of the Co- 

 lorado ; a river lyin^ about eighty miles northward of the Rio 

 Negro. When General Rosas left Buenos Ayres he struck in a 

 direct line across the unexplored plains : and as the country was 

 thus pretty well cleared of Indians, he left behind him, at wide 

 intervals, a small party of soldiers with a troop of horses 

 {a posta), so as to be enabled to keep up a communication with 



* Linnsean Trans., vol. xi. p. 205. It is remarkable how all the circum- 

 stances connected with the salt-lakes in Siberia and Patagonia are similar. 

 Siberia, like Patagonia, appears to have been recently elevated above the 

 waters of the sea. In both countries the salt-lakes occupy shallow depres- 

 sions in the plains ; in both the mud on the borders is black and fetid ; be- 

 neath the crust of common salt, sulphate of soda or of magnesia occurs, i;n- 

 perfectly crystallized ; and in both, the muddy sand is mixed with lentils of 

 gypsum. The Siberian salt-lakes are inhabited by small crustaceous ani- 

 mals ; and flamingoes (Edin. New Philos. Jour., Jan. 1830) likewise frequent 

 them. As these circumstances, apparently so trifling, occur in two distant 

 continents, we may feel sure that they are the necessary results of comm.on 

 causes. — See Pallas s Travels, 1793 to 1794, pp. 129-134. 



r2 



