1855.] MURCHISON AND MORRIS — THURINGERWA.LD. 413 



which are several beds with Nereites^ Orthis resembling O. grandis^ 

 Sil. Syst., and Beyrichia comjplicata, whilst the schists contain many 

 Graptolites. Whether there be Fucoids and Annelids in the lowest 

 of these strata, or Trilobites, including Ogygice^ of the type of 

 O, (Asaphus) Buchiiy Orthidce, and Graptolites in the central and 

 superior portions of the same, we have elsewhere* enumerated a 

 sufficient number of fossils to leave no doubt of the true Silurian 

 age of these grey-coloured slaty rocks, as recognized by M. Richter. 

 In abundance of Graptolites and Annelids the Lower Silurians of the 

 Thiiringerwald bear, indeed, a most striking resemblance to the strata 

 of the same age in the south of Scotland, which like them repose on 

 rocks wherein no remains of animal life have yet been detected. 



It is well worthy of note that several species of the Graptolites 

 of the Thiiringerwald and adjacent parts of Saxony are identical 

 with British and particularly with Scottish types, and are also known 

 in Bohemia, Scandinavia, North America, &c. The larger Nereites 

 and the Protovirgularia dichotoma of this tract are also identical 

 with Scottish types collected by Harkness and compared by Salter. 



The impure limestone (6+) lies in the upper portion of the series, 

 and in it and the associated shale are found Graptolites priodon 

 {LudensiSy Sil. Syst.) and other Graptolites, with Orthoceras Bohe- 

 micum ? (O. Ibex), O. styloideuwiy and a Crinoid resembling Crota- 

 locrinus. M. Barrande had suggested that this band might represent 

 the base of the Upper Silurian of Bohemia or the lower part of the 

 Wenlock ; but, judging from any fossils we saw, we are unable to 

 confirm this idea. For, whilst in Bohemia the Graptolite shales 

 clearly overlie the mass of the Lower Silurian rocks, we know that in 

 Britain the very same species of Graptolites descend into the inferior 

 division of the Llandeilo formation f. 



All these rocks have a strike from N.E. to S.W., which is there- 

 fore at right angles to the geographical axis or watershed of the 

 chain, whilst the prevalent dip is to the S.E. It must here, how- 

 ever, be noted, that slaty cleavage planes are in general so prevalent, 

 their dip being persistently to the N.W., that true observations on 



* ' Siluria/ p. 352, 353. 



f "Whilst this memoir was passing through the press I received a letter from 

 M. Richter, of Saalfeld, in which he states, that in the Lower Silurian slates there 

 occur Nereites, Myrianifes, Lophoctenium, Orthis, Orbicula, Cladograpsus, Phy- 

 topsis, Palmophycus, Buthotrephis. In the conglomerates which alternate with 

 the Nereite beds are found Beyrichia complicata, Salt.; some undetermined Tri- 

 lobites, Orthis redux, Barr., O. testudinaria, Dalm., O. alternata, ? * Sil. Syst.,' 

 O. lata, ib., Leptcena sericea, ib., Pentamerus oblongus and P. globosus, ib., Fenes- 

 tella subantiqua, D'Orb., Petraia subduplicata, M'Coy, Sarcinula organum ?, Linn., 

 Nidulites favus ?, Salt., and a Coral which was sent by me to my friend Mr. Lons- 

 dale, who pronounced it to be a Plcurodictyum. M. Richter has since described it 

 as a species distinct from the P. problematicum of the Devonian rocks, and has 

 named it P. Lonsdalei. M. Richter confirms my view of the absence of all Devo- 

 nian rocks except the Upper or Cypridina group, which he divides into two stages. 

 As he has not observed any union between the Upper Devonian and the lowest 

 Carboniferous strata, it is probable that there is a break, and that the Productus 

 limestone and Kieselschiefer (which are present at Hof) being absent, the Upper 

 Devonian of Saalfeld is at once succeeded by the equivalent of the Millstone grit — 

 or " floetz-leerer Sandstein" of the Germans. — R. I. Murchison, Sept. 15, 1855. 



2 F 2 



