BITUMEN SPRINGS. 397 



kalfc, quadersandstein, Jura limestone, secondary sandstone 

 with lignites (green and iron sand), and the tertiary 

 strata lying above chalk, I believe that the bitumen whicn 

 everywhere accompanies gem-salt, and most frequently salt- 

 springs, characterizes the muriatiferous clay of the peninsula 

 of Araya and the island of Marguerita, as linked with 

 formations lying below the tertiary strata. I do not say 

 that they are anterior to that formation, for since the pub- 

 lication of M. von Buch's observations on the Tyrol, we 

 must no longer consider what is below, in space, as neces- 

 sarily anterior, relatively to the epoch of its formation. 



Bitumen and petroleum still issue from the mica-slate; 

 these substances are ejected whenever the soil is shaken by 

 a subterranean force (between Cumana, Cariaco, and the 

 Golfo Triste). Now, in the peninsula of Araya, and in the 

 island of Marguerita, saliferous clay impregnated with bitu- 

 men is met with in connexion with this early formation, 

 nearly as gem-salt appears in Calabria in flakes, in basins 

 inclosed in strata of granite and gneiss. Do these circum- 

 stances serve to support that ingenious system, according 

 to which all the co-ordinate formations of gypsum, sulphur, 

 bitumen, and gem-salt (constantly anhydrous) result from 

 floods passing across the crevices which have traversed the 

 oxidated crust of our planet, and penetrating to the seat of 

 volcanic action. The enormous masses of muriate of soda 

 recently thrown up by Vesuvius,* the small veins of that 

 salt which I have often seen traverse the most recently 

 ejected lavas, and of which the origin (by sublimation) 

 appears similar to that of oligist iron deposited in the same 

 vents,t the layers of gem-salt and saliferous clay of the 

 trachytic soil in the plains of Peru, and around the volcano 

 of the Andes of Quito, are well worthy the attention of 

 geologists who would discuss the origin of formations. In 

 the present sketch I confine myself to the mere enumeration 

 of tne phenomena of position, indicating, at the same time, 

 some theoretic views, by which observers, in more advan- 



* The ejected masses in 1822, were so considerable, that the inhabi- 

 tants of some villages round Vesuvius, collected them for domestic 

 purposes. 



t Gay-Lussac, on the action of voloanos, in the Annales de Chimie, 

 vol. xxii, p. 418. 



