636 



frequently salt-springs, characterizes the mu- 

 riatiferous clay of the peninsula of Araya, and 

 the island of Marguerita, as linked with forma- 

 tions placed below the tertiary soil. I do not 

 say that they are anterior to that soil, for 

 since the publication of M. de Buch's observa- 

 tions on the Tyrol, it is no longer permitted to 

 consider what is below, in space, as necessarily 

 anterior, relatively to the epocha of its forma- 

 tion. 



The bitumen and petroleum still issue, as 

 we have shewn above (Vol. ii, p. 290 ; Vol. vi, 

 p. 97), from micaslate; these substances are 

 ejected whenever the soil is shaken by a sub- 

 terranean force (between Cumana, Cariaco, 

 and the Golfo Triste). Now, in the peninsula 

 of Araya, and in the island of Marguerita, sali- 

 ferous clay impregnated with bitumen is fixed 

 to this primitive soil, nearly in the same man- 

 ner as gem-salt appears in Calabria by frag- 

 ments in the basins, inclosed in soils of granite 

 and gneiss *. Do these circumstances serve to 

 support the ingenious system -f- according to 

 which, all the co-ordinate formations of gyp- 

 sum, sulphur, bitumen, and gem-salt (con- 



* Melograni, Descr. geologica di Aspromonte, 1823, p. 

 256, 276, 287. 



+ Breislak, Geologia, Vol. \, p. 350 j Bout sur les AVpes, 

 p. 17. 



