Geological Society of London. 329 



Etage Tongrien (therefore not Eocene), and is equivalent to tlie Oligocene clay of 

 Boom in Belgium, and, therefore, also with the Septaria clay of Berlin. 



Eocene Eruptive Rocks, Teschenite, contains Hornblende, Augite, JMephelin, Anor- 

 thite-like-trickline felspar. Accessories to these are Apatite and Carbonate of Lime ; 

 Diorite and Diabase ; Aphanite and Aphinitic Amygdaloid. 



B. Mwce>ie Deposits. — These cover the whole south and western part of Upper 

 Silesia, with the exception of the higher elevated country. South, the Cretaceous 

 rocks and Eocene deposits of the Karpathians; "West, the Devonian rocks of the 

 Gesenke ; East, Jurassic hills of Krakau-Wielun. 



This extensive Miocene basin communicates with the basin of Vienna-Moravia, 

 only through the channel of Mahrisch-Ostrau, and Prerau, which is only from two 

 to four miles broad. The thickness of these deposits is from 500 to 700 feet. They 

 rest generally on rocks of the Carboniferous formation. 



a. Lower group (Marine Clay and Leitha Limestone). Thickness, 500 to 700 feet. 



Bluish Grey Clay, mixed with quartzose sands, and containing much lime. 

 Equivalent to the Lower Marine Clay of Vienna. Beds of light yellow 

 limestone, very rich in fossils. The latter are of the same age as the Leitha 

 limestone of Vienna. They contain also gypsum and rock-salt (Wieliczka 

 and Bochnia, in Austria). (A list of the fossils is given at pages 375-394.) 



b. Upper group. "White sands and clay, with iron-ores, near Kieferstadtel and 



Stanitz. "Lignite. Limited to the country between Rybnik and Ujest. 

 Eemains of Prox furcatus, Hensel, an Indian form. In Upper Silesia are 

 wanting the brackish and freshwater deposits, the Cerithium and Congeria 

 beds of Vienna. 



C. Oligocene Lignite beds. — Grey, richly coloured or white plastic clay and white 

 sand, alternating with layers of Lignite and Iron-ores, and freshwater Quartzites 

 many hundred feet in thickness. 



Basalt.— Only known west of the river Oder; to be looked upon as the most 

 eastern offshoots of the Basalts of the Eifel, which, beginning at the left banks of 

 the Ehine, strike E. across South Germany, Bohemia, and Silesia. Between the 

 Oder and Ural mountains no Basalt is known. 



Diluvium, consisting of the usual sand, gravel, and clay (Loss), covers the greater 

 part of Upper Silesia, with the exception of the highest points. It belongs to the 

 same epoch and fauna as the Diluvium of the Ehine near Basel, etc., etc., with 

 Elephas primigenius. Rhinoceros tiehorhinus. Bison prisons, and Bos primigenius. 



There is a very interesting report by Dr. Eunge, of Breslau, on the occurrence and 

 the production of useful minerals of Upper Silesia, Mith numerous maps and sections, 

 etc., which forms part of Dr. Roemer's book, but which it is not possible to treat 

 with requisite consideration here. 



"We cannot but express our obligations to Dr. Ferdinand Eoemer for his most 

 valuable work. — C. L. G. 



I^E:POI^TS J^IsTID I^iaOGIBiEIDII^rG-S. 



Geological Society of London. — May 10, 1871. — Prof. Morris, 

 Vice-President, in the Chair. The following communications were 

 read: — 1. "On the Ancient Eocks of the St. David's Promontory, 

 South Wales, and their Fossil contents." By Prof. E. Harkness, 

 F.E.S., F.G.S., and Henry Hicks, Esq. 



In the Promontory of St. David's the rocks upon which the con- 

 glomerates and purple and greenish Sandstone, forming the series 

 usually called the " Longmynd " and " Harlech Groups," repose, are 

 highly quartziferous, and in many spots so nearly resemble syenite, 

 that it is at first difficult to make out their true nature. The appa- 

 rent crystals are, however, for the most part angular fragments of 

 quartz, not possessing the true crystalline form of the mineral. The 

 matrix does not exhibit a crystalline arrangement, and contains a 



