18 Nelafioiis of T raj)- Forks tc/'th Ores of Copper. 



StifFt, Leonardt, de Dechen, &c., have described the charac- 

 ters of these rocks, and distinguished from the schalstein, 

 properly so called, \st, The kalktrnp, which are compact 

 rocks, homogeneous, green or red, characterised by a mix- 

 ture of limestone with the elements of the greenstone ; 2d, 

 The mandelstein, which are nothing else than our amygda- 

 loids, rocks of contact which connect the preceding with the 

 greenstone. 



M. Oppennann published, in 1836, a treatise on the schal- 

 stein and kalktrap, in which he reviews all the opinions pre- 

 viously published. These rocks, he says, are situate at the 

 contact of the greenstone with the greywackes, slates, or 

 limestones, in such a manner that, according to the loca- 

 lities, they may be studied in very different media, whose 

 characters they reflect. M. Becher has studied the schal- 

 stein principally in the limestone foi'mation, Walchner in 

 the formation of clay-slate, and Stifft in the greenstone ; 

 so that each of them has characterised these rocks by the 

 predominance of lime, clay, or magnesia. 



All these observers appear to agree in regarding the schal- 

 stein, kalktrap, and mandelstein, as rocks subordinate to 

 gi'eenstone, forming the passage between the crystalline 

 rocks and the argillaceous or limestone rocks. Some of 

 them, however, have separated the argillaceous schalstein, 

 which they consider as a normal rock subordinate to the slaty 

 rocks ; while the kalktrap and the mandelstein cannot be 

 supposed to have any other origin than the greenstone. 

 With regard to ourselves, we consider all these varieties as 

 metamorphic rocks. 



If we set aside the amygdaloids, the schalstein exhibits the 

 greater part of the characters assigned to the green and red 

 gabbro of Italy. By the amygdaloids and subordinate beds 

 of oligistic iron, they become confounded with the blatter- 

 stein of the Harz. 



All the considerations we have brought forward to shew 

 that the gabbro is stratified, may be applied to the schal- 

 stein and blatterstein, for these thi"ee types of rocks present 

 remarkable resemblances in the conditions of their posi- 

 tions. All the three are found towards the outskirts of the 



