BlTUilES SPKIKGS. 
397 
kallc, quadursandstein, Jura limestone, secondary sandstone 
with lignites (green and iron sand), and the tertiary 
strata lying above chalk, I believe that the bitumen which 
everywhere accompanies gem-salt, and most frequently salt- 
springs, characterizes the mnriatiterous clay ot the peninsula 
of Araya and the island of hlarguerlta, 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. voir Buch’s observations on the Tyrol, we 
must no longer consider what is below, in space, as neces- 
sarily anterioi', relatively to the epoch of its formation. 
Bitumen and petroleum still issue from the mica-slate ; 
tdiese substances are ejected whenever tlie soil is shaken by 
a subterranean force (between Cumana, Cariaco, and the 
Golfo Tristc). bfow, in the peninsula of Araya, and in tin? 
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 
inclokHl in strata of granite and gneiss. Do these circum- 
stances servo 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 tlie seat of 
volcanic action. The enormous masses of muriate of soda 
recently thrown up by Vesuvius,* the small veins of that 
salt wiiicli I have often seen traverse the most recently 
ejected lavas, and ot which the origin (by sublimation) 
appears similar to that of oligist iron deposited in the same 
vents,)* the layers ot 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 aitention of 
geologists who would discuss the origin of formations. In 
the present sketch I confine myselt to tlie mere enumeration 
of the 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. ... , j ■ 
+ Gay-Lussac, on the action of volcanos, in the Annales de Lhimie, 
vol. xxii, p. 418. 
