631 



sometimes enclosed in it like the gypsum of 

 Golfo Triste on the east of the (Alpine) lime- 

 stone of Cumanacoa. Perhaps the great masses 

 of sulphur (Vol. iii, p. 104 ; Vol. iv, p. 50, 386). 

 found in the layers, almost entirely clayey, of 

 the steppes (Guayuta ; valley of San Bonifacio ; 

 Buen Pastor ; confluence of the Rio Pao with 

 the Oroonoko), belong to the marl of the gyp- 

 sum of Ortiz? These clayey beds are so much 

 more worthy of the attention of travellers, since 

 the fine observations of M. de Buch, and several 

 other celebrated geognosts, on the cavernosity 

 of gypsum, the irregularity of the inclination of 

 its strata, and its parallel position with the two 

 declivities of Harz, and the (heaved-up) chain 

 of the Alps, on the simultaneous presence of 

 sulphur, oligist iron *, and the sulphurous acid 

 vapours which preceded the formation of sul- 

 phuric acid, seem to manifest the action of 

 forces that reside at a great depth in the in- 

 terior of the globe -f\ 



* Gypsum with oligist iron in the variegated sandstone, 

 south of Dax (department of the Landes). 



+ Leopold von Buch, Resultate geogn. Forsch., 18*24, p. 

 471-473. Friedrich Hofmann, Beitr. zur geogn. Kenntniss von 

 Norddeutschland, 1822, Vol. i, p. 85, 92. Bou<?, Mem. sur 

 les terrains second, du versant nord des Alps, p. 14. Freies- 

 leben, Kupferschiefer, 1809, Vol. ii, p. 124. Boeislak, Geol, 

 Vol. i, p. 255. 



