We 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 sometimes in transition gypsum,* (* Uebergangsgyps, in the transition slate of White Alley (l'Allee Blanche), and between the grauwacke and black transition limestone near Bex, below the Dent de Chamossaire, according to M. von Buch.) sometimes in the Alpine limestone,* (* At Halle in the Tyrol.) sometimes in a muriatiferous clay lying on a very recent sandstone,* (* At Punta Araya.) and lastly, sometimes in a gypsum* posterior to the chalk. (* Gypsum of the third formation among the secondary gypsums. The first formation contains the gypsum in which are found the brine-springs of Thuringia, and which is placed either in the Alpine limestone or zechstein, to which it essentially belongs (Freiesleben Geognost. Arbeiten tome 2 page 131), or between the zechstein and the limestone of the Jura, or between the zechstein and the new sandstone. It is the ancient gypsum of secondary formation of Werner's school (alterer flozgyps), which we almost preferably call muriatiferous gypsum. The second formation is composed of fibrous gypsum, placed either in the molasse or new sandstone, or between this and the upper limestone. It abounds in common clay, which differs essentially from the salzthon or muriatiferous clay. The third formation of gypsum is more recent than chalk. To this belongs the bony gypsum of Paris; and, as appears from the researches of Mr. Steffens (Geogn. Aufsatsze 1810 page 142), the gypsum of Segeberg, in Holstein, in which sal-gem is sometimes disseminated in very small nests (Jenaische Litteratur-Zeitung 1813 page 100). The gypsum of Paris, lying between a cerite limestone, which covers chalk and a sandstone without shells, is distinguished by fossil bones of quadrupeds, while the Segeberg and Lunebourg gypsums, the position of which is more uncertain, are characterized by the boracits which they contain. Two other formations, far anterior to the three we have just mentioned, are the transition gypsum (ubergangsgyps) of Aigle, and the primitive gypsum (urgyps) of the valley of Canaria, near Airolo. I flatter myself that I may render some service to those geologists who prefer the knowledge of positive facts to speculation on the origin of things, by furnishing them with materials from which they may generalize their ideas on the formation of rocks in both hemispheres. The relative antiquity of the formations is the principal object of a science which is to render us acquainted with the structure of the globe; that is to say, the nature of the strata which constitute the crust of our planet.)

The new salt-works of Araya have five reservoirs, or pits, the largest of which have two thousand three hundred square toises surface.

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