of the 'European Rocks. ■i't? 



Group 7. {Carboniferous) Coal-measures and carboniferous 

 limestone. The former would appear in the greater number 

 of instances to be naturally divided from the group above it, 

 but the latter would seem more allied to that beneath : there 

 is however so much connection in this country between the 

 coal-measures and the carboniferous limestone, that it would 

 appear convenient for the present to keep them together. 

 Judging from Europe, the coal-measures present us with the 

 largest mass of fossil vegetables. 



Coi'als were common, but they occur in as great abundance, 

 if not more plentifully, now; though the recent species, ge- 

 nerally speaking, differ from the fossils. But Productse, the 

 abundance of which characterizes this group, are now un- 

 known ; and the Crinoidea which occur in these rocks in 

 multitudes are very rarely found in a living state. 



Group 8. {Grati-jcacJce) This may be considered as a mass 

 of sandstones, slates and limestones, in which sometimes one 

 predominates, sometimes the other; the old red sandstones of 

 the English geologists being the upper of its sandstones. Tri- 

 lobites are the most remarkable and abundant fossils of this 

 epoch, and corals and orthoceratites occur in great numbers. 

 It is difficult to fix the inferior limits of this group. 



Group 9. [Lowest Fossiliferoiis) It is very difficult in the 

 present state of our knowledge to say whether or not this con- 

 stitutes a separate group from No. 8 ; and I have here intro- 

 duced it more in accordance with the views of other geologists 

 than with my own. A difference in mineralogical structure 

 proves nothing; the changes in this respect are so various, 

 that the different appearance of one slate from another, if 

 not shown to occupy a different geological position, is of no 

 value. It has indeed been supposed that the Snowdonian 

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

 the proof of this. 



Inferior or Non-fossiliferous Stratified Rocks. — It 

 would be useless in a sketch of this nature to enumerate the vari- 

 eties of slates and other rocks that enter into this division, they 

 will readily present themselves to the mind of the geologist; re- 

 cent observations show that many rocks to all appearance of 

 this division may belong to the preceding. M. Elic de Beau- 

 mont, in one of his late letters to me, states, that mounting the 

 Val Bedretto from Airolo to the foot of the Col, which leads into 

 the Ilaut Valhiis, he found "an alternation many times re- 

 peated of small beds of a compact and grey-black limestone, 

 and a nearly black limestone mixed with clay slate thickly 

 studded with crystals of garnets and staurotides. Both the 



one 



