dies buried in the countries of the north exhi- 

 bits, were I not afraid of increasing the number 

 of geological dreams. 



The basalts of Regla, sketched on this plate, 

 offer an undeniable proof of that identity of 

 form, which is observed among the rocks of 

 different climates. The mineralogical traveller, 

 who casts a look over this drawing, finds in it 

 the form of the basalts of the Vivarias, of the 

 Euganean mountains, or of the promontory of 

 Antrim in Ireland. The slightest circumstances 

 observable in the columnar rocks of Europe are 

 perceived in this group of the basalts of Mexico. 

 So great an analogy of structure leads us to 

 suppose, that the same causes have acted under 

 every climate, and at very different epochas ; 

 for the basalts covered with thonschiefer and 

 compact limestone must be of a very different 

 age from those, that repose on strata of coal and 

 pebbles. 



The cascade of Regla is to the north-east of 

 Mexico, at a distance of twenty-five leagues, 

 between the celebrated mines of Real del 

 Monte, and the thermal waters of Totonilco. 

 A small river, which moves the wheel of the 

 mill for amalgamation at Regla, the construc- 

 tion of which cost more than ten millions of 

 livres, forces its way across the groups of ba- 

 saltic columns ; the sheet of water that rushes 

 down is considerable, but the fall is not above 



VOL. XIII. T 



