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34 Sketch of a Classification of the Eiiropfan Roch^. 



speaking, differ from the fossils. But Producta}, the abundance of 

 which characterizes this group, are now unkno^vIl; and the Crinol- 

 dea which occur In these rocks in multitudes are very rarely found 



in a living state. 



Group 8. {Grauwacke) This may be considered as a mass of 



sandstones, slates and limestones, in which sometimes one predomi- 

 nates, sometimes the other; the old red sandstones of the English 

 geologists being the upper of its sandstones. Trilobites are tlie most 

 remarkable and abundant fossils of this epoch, and corals and ortho- 

 ceratltes occur in great numbers. It is difficult to fix the inferior 



limits of this group. 



Group 9. {^Lowest Fossiliferons) It is very difficult in the present 

 state of our knoAvledge to say whether or not this constitutes a sepa- 

 rate group from No. 8 ; and I have here introduced it more in ac- 

 cordance with the views of other geologists than with my own. A 

 difference in mineralogical structure proves nothing; the changes 

 n this respect are so various, that the different appearance of one 

 slate from another, if not shown to occupy a different geological po- 

 sition, is of no value. It has indeed been supposed that the Snow- 

 donian slates are older than the grauwacke series, but we yet require 

 the proof of this. 



Inferior orNon-fossiliferous Stratified Rocks. — It would 

 be useless in a sketch of this nature to enumerate the varieties of 

 slates and other rocks that enter into tliis division, they will readily 

 present themselves to the mind of the geologist ; recent observations 

 show that many rocks to all appearance of this division may belong 

 to the preceding. M- Elie de Beaumont, in one of his late letters 

 to me, states, that mounting the Val Bedretto from Airolo to the 

 foot of the Col, which leads info the Haut Vallais, he found " an al- 

 ternation many times repeated of small beds of a compact and grey- 

 black limestone, and a nearly black limestone mixed with clay slate 



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thickly studded with crystals of garnets and staurotides. Both the 

 one and the other of these rocks contain a considerable number of 

 belemnites transformed into white calcareous spar, but of which the 

 general forms and alveoli are nevertheless very visible, and can 

 leave no doubt as to the nature of the fossils* As these limestone 

 beds are the prolongation of those in which the gypsum of the Val 

 Canaria is found, and as these are the same with those in which the 

 dolomite of Campo Longo occurs, we can assure ourselves that all 

 the curious mineralogical phaenomena of the St. Gothard have been 



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