358 Mr. Weaver on flaetx Formations. [Nov. 



and clay, and reposing on a similar series ; while in most 

 places, it is found in the lowest beds, adjoining to the subjacent 

 cavernous gypsum and limestone. But in all these cases, it 

 forms isolated, shapeless, masses, lodged in the clay ; the largest 

 and most connected appearing in the lowest position, and the 

 more divided and numerous in the intermediate and uppermost. 

 Yet in those parts, where the gypsum masses are wanting, traces 

 of this mineral are still to be met with, in the form of round 

 nests, single grains, or thin streaks. The enveloping mass most 

 frequently consists of the red, slaty, tenacious clay, pure, or fine 

 saudv ; it, however, often alternates with layers of sand, or ten- 

 der sandstone ; and in some quarters it contains boulders and 

 pebbles of quartzy sandstone, granite, syenite, &c. of various 

 sizes, and disposed in layers, e.g. near Wolferode andWimniel- 

 burg. 



The sand gvpsum is to be observed near Grosleinungen, in 

 connected masses, forming a continuous chain of cliffs, where it 

 reposes on an alternating series of beds of calcareous sandstone, 

 indurated marl, limestone, and sandstone ; and which separate 

 there the sand gvpsum from the subjacent swinestone and 

 lower gvpsum. This sand gypsum contains frequently layers 

 and streaks of red clay, large round masses of firm sandstone, 

 and lamellar portions of slaty micaceous sandstone. 



The principal constituents of the upper gypsum are the 

 foliated and radiated kinds, with a smaller proportion of the 

 specular, fibrous, and earthy ; being found grey, white, bluish, 

 or reddish. In the clay gypsum are also found occasionally 

 carbonate of lime in spots and stripes, and small rock crystals in 

 prisms with both the pyramidal terminations, e. g. near Wimmel- 

 burg. Native sulphur has likewise occurred in it near Naundorf. 



In Mansfeld, the thickness of the upper gypsum has been 

 found varving, in different places, from 2 to 30 fathoms. 



Rock-Hi'/i. — Several geologists are of opinion that saltsprings 

 derive their source from the clay and gypsum of the new red 

 sandstone formation. It does not appear that salt springs always 

 proceed directly from a body of rocksalt, or from salt connected 

 with the gypsum, but frequently rather from saline particles 

 diffused through the clay. Hence the clay, as well as the gyp- 

 sum, may be said to be saliferous. This view of the case is 

 confirmed by experience. 



At Schombeck, in Magdeburg, salt springs rise from abed of 

 clay, immediately below the shell limestone ; and at Aschersle- 

 beii, near Halberstadt, a salt spring rises either from shell lime- 

 stone, or from the clay of the new red sandstone formation ; 

 while at Salzhennersdorf, in Hanover, salt springs proceed from 

 the upper gvpsum. In the forest of Thuringia, salt springs issue 

 from the bed of clay that lies below the new red sandstone, near 

 Salzungen and Schmalkalden. Near Sulz on the 11m, Lindenau 

 in Hildburgshausen, and Kreuzburg in Eisenach, they proceed 



