GEOLOGICAL SOCIETY OF LONDON. 



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been obtained from an examination of the organic remains 

 of the Berwyns ; hence he concludes, that, in the great 

 section of North Wales, there is no positive geological dis- 

 tinction in the successive descending groups, the only- 

 difference being the gradual disappearance of species which 

 occur in the higher beds. 



Cumbrian Groups. — The groups exhibited in a section 

 from Keswick through Kendal to Kirby Lonsdale are-— 1st, 

 that of Skiddaw Forest ; 2nd, a group essentially composed 

 of quartzose and chloritic roofing slates, associated with 

 innumerable igneous rocks, and bounded by calcareous slates, 

 which extend from the south of Cumberland to the neigh- 

 bourhood of Shap Fells ; 3rd, a great series of beds, ranging 

 from the calcareous slates to the carboniferous series, and 

 separated provisionally, by the author, into two divisions ; 

 the lower consisting of slates and flagstones, with occasionally 

 thick, hard, arenaceous strata, the fossils containing many 

 species characteristic of the lower Silurian rocks, and the 

 upper being composed of arenaceous flagstones, with beds of 

 hard greywacke, calcareous matter occasionally occurring, but 

 no beds of limestone fit for use. The fossils of this division 

 contain numerous species belonging to the upper Silurian 

 rocks of Mr. Murchison, or to the beds which have been 

 considered to form the base of the old red sandstone in 

 Shropshire. From the above specific determinations of 

 organic remains, the author says, the following definite in- 

 formation is obtained, viz., that the lower division is lower 

 Silurian, and that the upper ends at the very top of the 

 Silurian system. Two other sections are then briefly no- 

 ticed. One from the Shap granite through the fossiliferous 

 slate of Howgell Fell, the beds of which are placed in the 

 upper division of the upper Silurian system, but not the 

 highest part ; and the other from the v/estern boundary of 

 the calcareous slates to Ulverston, including, 1, the calcareous 

 slates (Caradoc) of Millom, in Cumberland ; 2, quartzose 



