L80 
SALT-WORKS OUT AHAYA. 
to the heat of the sun, evaporate at their surface ; crusts 
of salt, formed in a saturated solution, fall to the bottom ; 
and by the attraction between clirystals of a similar nature 
and form, the crystallized masses daily augment. It is 
generally observed that the water is brackish wherever 
lagoons are formed in clayey ground. It is true, that for 
the new salt-work near the battery of Araya, the sea- 
water is received into pits, as in the salt marshes of the 
south of France; but in the island of Margarets, near 
Pampatar, salt is manufactured by employing only fresh 
water, with which the muriatiferous clay has first been 
lixivated. 
We must not confound the salt disseminated in these 
clayey soils with that contained in the sands of the sea- 
shore, on the coasts of Normandy. These phenomena, 
considered in a geognostieal point of view, have scarcely 
any properties in common. I have seen muriatiferous 
clay at the level of the ocean at Punta Araya, and at 
two thousand toises’ height in the Cordilleras of New 
Grenada. If in the former of these places it lies on very 
recent shelly breccia, it forms, on the contrary, in Austria 
near Isehel, a considerable stratum in the Alpine lime- 
stone, which, though equally posterior to the existence of 
organic life on the globe, is nevertheless of high antiquity, 
as is proved by the great number of rocks with which it 
is covered. ¥e shall not question, that sal-gem, either 
pure or mixed with muriatiferous clay, may have been 
deposited by an ancient sea; but everything evinces that 
it was formed during an order of things bearing no 
resemblance to that in which the sea at present, by a 
slower operation, deposits a few particles of muriate of 
soda on the sands of our shores. In the same manner 
as sulphur and coal belong to periods of formation very 
remote from each other, the sal-gem is also found some- 
times in transition gypsum,* sometimes in the Alpine lime- 
stonef, sometimes in a muriatiferous clay lying on a very 
* Uebergangsgyps, in the transition slate of White Alley (l’Allea 
Blanche), and between the grauwacke and black transition limestone neat 
Bex, below the Dent de Chamossaire, according to M. von Buch. 
t At Halle in the Tyrol. 
