436 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Apr. 4, 



thrown some additional light on the western extremity of the region 

 which Roemer has coloured in his map as Silurian ; though it must 

 be observed that some of the most unequivocal of our Silurian locali- 

 ties are therein laid down as "Culm." After describing four classes 

 of sedimentary rocks under the terms of Grauwacke, Grauwacke- 

 schiefer, Thon-schiefer, and Quarzfels, besides other rocks of meta- 

 laorphic or igneous origiu, he indicates that which we shall presently 

 speak of as a series of true Carboniferous strata, as originally stated 

 in the * Transactions of the Geological Society,' 2 ser. vol. vi. 



The same author also mentions, towards the close of his paper, a 

 considerable mass of limestone to the north of Wieda which is fos- 

 siliferous. Not having seen the organic remains of that rock, we 

 cannot affirm that this limestone is truly Silurian, as believed by M. 

 Adolf Roemer, though, if its organic remains be correctly identified, 

 we have little doubt that M. Barrande would class the rock with the 

 Upper Silurian of the Continent. The fossils are said to be, Tere- 

 bratula princeps (Barr.), T. bidentata (His.), Spirifer cultrijugatus 

 (Sow.), Cardium striatum (Sow.). 



Knowing as we now do, that, besides this mass to the north of 

 Wieda, there are numerous other protrusions of limestone which 

 have scarcely been examined, between that place and Harzgerode on 

 the east, and believing that these quasi-Silurian rocks on the south 

 are not separated from the unequivocal Devonian rocks of Elbin- 

 gerode on the north by any continuous band of eruptive rocks, we 

 trust that, notwithstanding the monotonous and covered outline of 

 the country, closer researches will obtain the requisite proofs of 

 order in an ascending series. 



Devonian Rocks. — These rocks occupy altogether a considerable 

 space to the east and south of the northern granitic axis, though 

 seldom in masses of any great, continuous extent. Like all the other 

 sedimentary formations, they occur, for the most part, in disjointed 

 masses, separated either by igneous or highly altered and metamor- 

 phosed rocks, so that the true sequence, even from one member of 

 the group to another, is seldom to be detected. The oldest unequi- 

 vocal Devonian stratum of the Harz, as on the Rhine, is the Spirifer- 

 sandstone with its associated slates and schists. The largest and 

 clearest exhibition of this rock is to be seen in the well-known hill of 

 the Rammelsberg, which overlooks the ancient town of Goslar from 

 the south, and which, owing to the aid of M. Zincken, who furnished 

 us with good fossils, was paralleled by Sedgwick and Murchison 

 with the shelly sandy *' grauwacke" of Coblentz. Clearly defined by 

 the presence of characteristic large Spirifers, the Plewodictyum pro- 

 blernaticum, a HomaloaotuSf and other fossils, there could be no 

 doubt respecting the age of this subformation, which here, as in the 

 Rhenish provinces, is associated with slaty schists, both underlying 

 and overlying. Thus, near Goslar, the slates of Nordberg, and others 

 to the south of the town, which are truly Devonian, seem, as formerly 

 indicated*, to pass by a great inversion under the Spirifer- sandstone, 



* Trans. Geol. Soc. Lond. 2 ser. vol. vi. p. 291. 



