156 Sketch of a Classification 



for some of the varieties of the carboniferous limestone. In 

 some places the new red sandstone contains an abundance of 

 vegetable remains, at others none can be detected in it. The 

 saurians first appear in the ascending series, at least in any 

 abundance, in this group. As I have before observed, the 

 lower part of this group generally rests unconformably on the 

 inferior rocks, and seems to have resulted from a veiy gene- 

 ral upheaving and fracture of the pre-existing strata, accom- 

 panied by the intrusion of trap rocks. 



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 carbonifei'ous 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. 



Corals 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. (Grauwaeke) 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 inferioMimits of this group. 



Group 9. (Lowest Fossiliferous) 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 varieties of 

 slates and other rocks that enter into this division, they will 

 readilv 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, 



