CXXVl PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



Tyrolj and Walgau in Bavaria are named ; and it is said that such 

 formation does not merely consist of the combustible shale which is 

 used for the production of asphalte, but also in many places, as in 

 the north-eastern Alps, of a black shining coal, called by Haidin- 

 ger " Alpine coal." 



The Keuper coal (Lettenkohle) occurs at the upper boundary of 

 the Muschelkalk. 



In the Permian strata of Saxony, a coal- deposit occurs, which was 

 considered to belong to the coal-formation until Von Gutbier pointed 

 out that the remains of plants which it contains were specifically di- 

 stinct from those of the true coal-formation. The " Brandschiefer," 

 previously described by Naumann, has yielded Lycopodites pinifor- 

 mis, Schlotheim, and Walchia Jilidformis, Schlotheim, amongst vege- 

 tables ; and of fishes, species of the genera AmblypteruSy Holocan- 

 thodes, Xenacanthus, and Cephalaspis, together with the thin shells 

 of a Cijpris, which much resembles the Posidonomya minuta. 



Coming now to the true coal-formation, M. Geinitz describes all 

 the varieties from a pitch-coal up to the " Stangenkohle," a natural 

 coke ; observing, that anthraeite must in most cases be considered 

 an altered coal ; and, taking the organic contents rather than the 

 mineral condition as the basis of arrangement, he recognizes the fol- 

 lowing varieties in the Saxon coal, though not separated from each 

 other by a strongly marked line; namely, — 1. The Sigillaria-coal, 

 consisting of thin beds of bituminous pitch- coal. 2. Calamite-coal, 

 containing Calamites cannceformis^ Schloth., C. Siickowii, Brong., 

 and C. approximatus, Schloth. ; as well sls Astei'ophyllites and Sphe- 

 nophyllum. 3. Fern-coal, thin-bedded and very bituminous. 4. Noeg- 

 gerathia-coal, a meagre, hard, slaty coal, in which occur Ncegyerathia 

 palmcEfor7ms, Goppert, and N. crassa, Goppert. 5. Sagenaria-coal, a 

 bituminous slaty coal. The culm-measures of Devonshire and Pem- 

 brokeshire are considered, with the mountain-limestone, to be the 

 equivalent of what in Germany is still called the '* younger grau- 

 wacke." The Sagenaria-coal above mentioned belongs to this divi- 

 sion ; and, as the mountain-limestone is deficient, Geinitz considers 

 that this coal, which differs so strongly in its organic contents from 

 that of Zwickau, and occurs in the Hainich-Ebersdorf coal-field, must 

 be considered as the Saxon equivalent of the mountain-limestone, 

 and be therefore classed with this division. 



Certain layers of coal in Saxony may be supposed to belong 

 to the devonian formation ; but, as the strata have suffered much 

 from the disturbance and metamorphic actions of igneous rocks, 

 some doubts mf^y exist as to their true position : in other countries, 

 however, the authority of De Verneuil is quoted for the probable 

 Devonian age of the rich coal-deposits of Sabeso between Oviedo 

 and Leon, the fossils of the strata associated with the coal being of 

 Devonian age, and that of Keyserling for the " Brandschiefer" of 

 Northern Russia. 



In the Silurian strata, though carbonaceous matter and alum-slates 

 may be found, no true coal can be expected, as hitherto but little 

 evidence of the existence of a land- or coast-flora has been discovered. 



