342 Mr. Weaver oh Floetz Formations. [Nov. 



proportion and intermixture of its earthy constituents with bitu- 

 men and metallic substances. In some places it passes even 

 into bituminous clay marl. Its average thickness is from 10 to 

 20 inches, while the roof or grey marl shale, which forms the 

 upper part of the bed, varies from four to eight feet in thickness. 

 The dip of the bed of marl shale is generally most rapid near the 

 outcrop, gradually acquiring a lower angle at a greater depth ; 

 but the position being very variable, it is found inclining nearly 

 under all angles between the vertical and the horizontal. 



In several quarters, the copper shale forms more beds than 

 one. Thus, for example, in the forest of Thuringia, it occurs in 

 the territory of Henneberg in several thin layers, sometimes 

 separate, sometimes coalescing ; and near Bennowitz it forms 

 thin beds, several feet apart, lying in the ferriferous limestone, 

 which there takes the place of zechstein, and is known by the 

 name of gryphite limestone. 



The non-metallic substances which occasionally appear in the 

 copper shale, are : quartzy sandstone, in elongated compressed 

 masses, six or eight feet in length, and three or four inches 

 thick ; compact limestone, in lenticular portions, or in layers ; 

 fibrous carbonate of lime, in frequent extremely thin layers, and 

 calcareous spar more rarely, in strings, and lining drusy cavities, 

 which sometimes appear several inches in extent ; fibrous gyp- 

 sum, in repeated thin layers, and, more rarely, foliated gypsum 

 in thin laminse ; drusy quartz in small veins ; mineral pitch, in a 

 pure state, in layers several lines in thickness ; coal, as the sub- 

 stance of animal and vegetable remains, and forming also lamellar 

 masses, one foot long, and one-fourth to half an inch in thick- 

 ness ; mineral charcoal, very rarely, in pieces eight or nine inches 

 long, and a half to one inch thick ; and mica, in disseminated 

 minute scales. 



The principal metallic substances found in the copper shale, 

 are ores of copper with iron pyrites, either intimately mixed or 

 in perceptible portions ; but beside these, blende, ores of cobalt 

 and nickel, and galena, are also met with ; while antimony, bis- 

 muth, arsenic, and native silver, are very rare. The ores are 

 generally found in the form of thin layers, slight strings, in small 

 nodules or grains, and disseminated ; sometimes also membra- 

 nous, or specular. But the native silver and native copper 

 occurred in the filiform, capillary, or membranous state. The 

 copper shale is extremely variable as to produce, of metal in 

 different parts of its course, being in some quarters not worth 

 smelting, and in others altogether barren. In those parts that 

 are sufficiently rich for metallurgic processes, the greatest thick- 

 ness adapted to the furnace is nine or ten inches, and the smallest 

 from two to five inches. 



Of animal remains, the following have been found in the 

 copper shale : skeletons, referred in general by Baron Cuvier to 

 the genus monitor ; of fishes, numerous impressions, skeletons 



