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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Apr. 4, 



the various angles of inclination which they present to the miner who 

 explores them. This tract oifers clear evidence, that the porphyritic 

 eruptions were not only violent, but successive and numerous during 

 the period of the Rothe-todte-liegende, and that they overflowed strata 

 of that formation in the form of submarine coulees. Here also, as 

 indeed in many other parts of Central Germany, we learn how these 

 dejections of contemporaneous porphyry and amygdaloid have been 

 occasionally so mixed up with pebbles and sand of the then existing 

 sea, as to render it difficult in such cases to decide whether the stra- 

 tum should be considered as one of igneous or of aqueous origin. In 

 all such extreme examples, however, the geologist who is seeking 

 after a truthful explanation of the works of nature will admit that 

 such strata are not to be dogmatically defined by one mineral term 

 only, but that, like the volcanic grit or ash of earlier periods, they are 

 to be viewed as true indications of the internal heat of the crust, which, 

 in bursting forth repeatedly, gave rise to those peculiar deposits which 

 resulted from a combination of subaqueous and volcanic causes. 



Weiss- or Grau-liegende — Kupfer-schiefer — Zechstein, ^c. 



Weiss-liegende. — The sandstones, breccias, and conglomerates of 

 which we have just spoken are succeeded in this region, as in many 

 other parts of Germany, by a band differing from all beneath it in 

 its light grey or whitish colour, as derived from a quantity of pebbles 

 of white quartz in a grey paste. This is truly a conglomerate made 

 up of rounded small stones, which present all the appearance of having 

 been formed by waves upon a shore. Since it forms the natural base 

 of the Copper-slate, the miners necessarily applied to it the name of 

 *' liegende," as underlying the productive mineral stratum. This bed 

 or band (for it varies in thickness from 3 or 4 feet to 30 or 40) may 

 be properly considered the base of the Zechstein or Magnesian lime- 

 stone division of the Permian rocks, since in it, after ascending through 

 the siliceous strata of the Rothe-todte-liegende, we first find calcareous 

 matter beginning to show itself, and with it a few rare fossils. 



Fig. 4. — Diagram showing the Succession of the Fermian Rocks on the 

 Flanks of the Thuringerwald. Horizontal distance about 4 miles. 



d. Lower Bunter. eS. Sandschiefer. "] 



c4. Upper Zechstein (Dolomite). 

 / 3. Lower Zechstein. ! Permian 



c2. Kupfer-schiefer. j Rocks, 



cl. Weiss-liegende. 

 b. Rothe-todte-liegende. J 



a. Coal-strata (Upper Coal). 

 p. Porphyry. 



The accompanying diagram (fig. 4) shows the position of this 

 Weiss-liegende, c^ ; and the open section in which we best saw it, as 



