74 



the pampas of Buenos Ayres, or the savannah 

 of the Missouri * and New Mexico, contain gra- 

 nitic blocks. The absence of this phenomenon 

 appears general in the New World : and is so 

 probably also in Sahara, in Africa ; for we must 

 not confound the rocky masses, that pierce 

 the soil in the middle of the desert, and of 

 which travellers often make mention, with sim- 

 ple, scattered fragments. These facts seem to 

 prove, that the blocks of Scandinavian granite, 

 which cover the sandy countries situate to the 

 south of the Baltic, and those of Westphalia and 

 Holland, are owing to a particular rupture com- 

 ing from the north, to a local revolution. The 

 ancient conglomerate (red sandstone), that co- 

 vers, according to my observations, a great part 

 of the llanos of Venezuela and of the basin of 

 the Amazon, contain no doubt fragments of the 

 same primitive rocks, as constitute the neigh- 

 bouring mountains ; but the convulsions, of 

 which these mountains exhibit evident marks, 

 do not appear to have been attended by circum- 

 stances favorable to the removal of great blocks. 

 This geognostic phenomenon was to me the 

 more unexpected, since there exists no where in 

 the world a smoother plain stretching as far as 

 to the abrupt declivity of the Cordjllera entirely 



* Are there any blocks in North America to the north of 

 the great lakes I 



