345 



(4.) Magnesian limestone — sometimes replaced by, or alternating 

 with, magnesian conglomerate. 



(5.) Red marl and gypsum — supposed to represent the " lower 

 red marl and gypsum" of the Yorkshire sections. (Geol. Trans, 

 vol. Hi. part I. p. 101.) 



(6.) Great, red and variegated sandstone of St. Bee's Head. 



From these facts the author draws the following conclusions : — 



1st. That in Cumberland, Durham, Yorkshire, and Shropshire, 

 there is the same succession of deposits overlying the carboniferous 

 order — that in all these regions the "lower red sandstone" (No. 2.) 

 represents the rolhe todte liegende or lowest division of the red sand- 

 stone series— and that in some cases thesame group (No. 2.) appears 

 to graduate into the true coal measures. 



2ndly. That the magnesian conglomerates are an integral part of 

 the formation of magnesian limestone, are superior to the "lower red 

 sandstone," and sometimes unconformable to it. 



3rdly. That the succession of deposits overlying the south- 

 western coal-fields of England is imperfect; inasmuch as the low- 

 est division of the new red sandstone series (No. 2.) is entirely 

 wanting ; — a fact easily explained by the discordant position of the 

 overlying groups, and the entire break of any continuity between 

 them and the coal measures. 



4thly. That the magnesian and porphyritic conglomerates of 

 the south-western districts of England (being in their mineral 

 structure and in their relations apparently identical with the mag- 

 nesian conglomerates of the northern counties) do not represent 

 the rothe todte liegende, but are on the higher parallel of the mag- 

 nesian limestone. 



§ 3. The author then briefly considers the classification adopted by 

 several continental writers, in which the old red sandstone, the car- 

 boniferous series, and the lowest division of the new red sandstone 

 series are regarded as one great complex group j and he endea- 

 vours to show, that, however adverse the English succession of the 

 older secondary formations may be to this view, it receives some 

 countenance from the development of the red sandstone and car- 

 boniferous series of Scotland. 



Lastly, he notices the great masses of red sandstone and conglo- 

 merate which fringe the Highland coasts, and doubling along the 

 south flank of the Grampians stretch from one side of Scotland to 

 the other. It is inferred, from their mineral structure and conti- 

 nuity, that they are of one epoch : and as one portion of them is 

 proved by Dr. Fleming to pass under the carboniferous series of 

 Fifeshire, it is inferred (in conformity with an opinion already pub- 

 lished by Mr. Murchison and the author) that, considered on the 

 whole, they are nearly on the parallel of the old red sandstone. It 

 is further shown that the Ichthyolites of Caithness and the Orkneys 

 cannot be separated from the same ancient group, and that they 

 are probably on the parallel of other ichthyolites discovered by Dr. 

 Fleming under the carboniferous series of Fifeshire ; — a conclusion 

 which does not appear to be invalidated by a single opposing fact. 



