older Deposits of the North of Germany and Belgium. 281 



Rhine, for about a mile above and below Caub, we found a slate-rock hardly to be distinguished from 

 the lower slates of the Ardennes. 



Below the fine slate zone of Caub, the rocks (though often with a true transverse slaty cleavage) are 

 more arenaceous, pass here and there into masses of psammite, contain bands that are highly fossili- 

 ferous (e.ff. the rocks on both sides of the Rhine for a mile or two above St. Goar, Lurleu, &c.), 

 and therefore, mineralogically as well as zoologically, agree more nearly with the upper slates of the 

 Ardennes. 



The two traverses, by the gorges of the Lieser and the Ees, which descend from the Eifel to Wittlich 

 and Lutzerath, present a similar sequence. 



(].) The fossiliferous marls, red slates, and psammites under the Eifel limestone. 



(2.) Great masses of slaty flagstone, &c. 



(3.) A great deposit of coarse arenaceous slate gradually passing, as M'e approach the banks of the 

 Moselle, into the structure of a true slate formation. The upper part is most fossiliferous, and what is 

 presumed (more on general analogy than on any evidence of sections) to be the lower part becomes 

 less and less fossiliferous. Occasionally, however, the lower slates are intersected by certain bands, in 

 which fossils are very numerous. Fine illustrations of the mineral structure of this third group, of its 

 contortions, and its great development, are seen in the noble gorges of the Moselle, above and below 

 Cochen ; and in the fine transverse gorge of the Ees between Lutzerath and Alf. 



On all these traverses, fossiliferous bands are found ; and the many forms of Orthis belong to the same 

 general group as those from the banks of the Rhine, and from the upper slates of Belgium and the Ar- 

 dennes. Hence all the rocks which are beneath the fossiliferous marls at the base of the Eifel limestone, 

 and are expanded through the districts we have last noticed, may be considered as a vast development 

 of the Silurian system, without any subordinate bands of limestone, or distinct subordinate formations, to 

 enable us to compare them with the subdivisions of that system in England. Hence also (with the excep- 

 tion of the more perfect slate rocks near Caub and on some parts of the right bank of the Moselle below 

 Treves, which may be provisionally assumed to represent the lower slates of the Ardennes (s7/steme 

 ardoisier inferieur), we may regard the same series of rocks as representing, in their higher psammites, 

 a portion of the lowest division of the systeme anthraxifere of Mons. D'Halloy and Professor Dumont ; 

 and in their lower arenaceous slates the systeme ardoisier superieur of the same authors. 



It remains for us to notice the chain of the Hundsriick and the Taunus, 

 which are one continuous formation, only split asunder by the gorge of the Rhine 

 immediately below Bingen. It appeared to us, after repeated examinations, that, 

 assuming the slate rocks near Caub to be the oldest members of the Rhenish 

 series, we had a regular ascending section, through arenaceous and earthy slates 

 and flagstones, to the quartz rock and fine chloritic schist of the Hundsriick and 

 the Taunus. We made five or six traverses through different gorges of these 

 chains, with a view of making out the facts of superposition ; and in every instance 

 we arrived at the same conclusion. If we can trust the evidence of sections, these 

 chains overlie the slaty rocks immediately skirting their north-western flanks. 



The beautiful crystalline structure of these chains, their fine masses of white 

 quartz rock, of chlorite slate, and micaceous slate, have led many authors to regard 

 them as the oldest rocks of the Rhenish provinces ; and this first error has been 

 confirmed by a second, in which slaty cleavage has been mistaken for stratification. 



