iULPnUBETTED SPRINGS. 10* 



made an excursion thither on a cool and misty morning 

 The waters, which are loaded with sulphuretted hydrogen, 

 issue from a quartzose sandstone, lying on compact lime- 

 stone, the same as that we had examined at the Morro. We 

 again found in this limestone intercalated beds of black 

 hornstein, passing into kieselschiefer. It is not, however, 

 a transition rock; by its position, its division into small 

 strata, its whiteness, and its dull and concho'idal fractures, 

 (with very flattenned cavities), it rather approximates to the 

 limestone of Jura. The real kieselschiefer and Lydian- 

 stone, have not been observed hitherto except in the transi- 

 tion-slates and limestones. Is the sandstone, whence the 

 springs of the Bergantin issue, of the same formation as 

 the sandstone of the Impossible and the Tumiriquiri ? The 

 temperature of the thermal waters is only 43*2 cent, (the 

 atmosphere being 27). They flow first to the distance 

 of forty toises over the rocky surface of the ground ; then 

 they rush down into a natural cavern; and finally they 

 pierce through the limestone, to issue out at the foot of the 

 mountain, on the left bank of the little river Narigual. 

 The springs, while in contact with the oxygen of the 

 atmosphere, deposit a good deal of sulphur. I did not col- 

 lect, as I had done at Mariara, the bubbles of air that rise 

 in jets from these thermal waters. They no doubt con- 

 tain a large quantity of nitrogen ; because the sulphuretted 

 hydrogen decomposes the mixture of oxygen and nitrogen 

 dissolved in the spring. The sulphurous waters of !San 

 Juan, which issue from calcareous rock, like those of the 

 Bergantin, have also a low temperature, (31'3) ; while in 

 the same region, the temperature of the sulphurous waters 

 of Mariara and Las Trincheras (near Porto Cabello), which 

 gush immediately from gneiss-granite, is 58'9 the former, 

 and 90'4 the latter. It would seem as if the heat which 

 these springs acquire in the interior of the globe, diminishes 

 in proportion as they pass from primitive to secondary 

 superposed rocks. 



Our excursion to the Aguaa Calientes of Bergantin 

 ended with a vexatious accident. Our host had lent us one 

 of his finest saddle-horses. We were warned at the same 

 time not to ford the little river of Narigual. We passed 

 over a sort of bridge, or rather some trunks of trees laid 



