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In contemplating the great number of beds here deposited, 

 we must remember that miUions of others must have occupied 

 the same area, and have been swept away without leaving a 

 trace, like those which we see daily in the neighbouring estuary 

 of the Severn, before the conditions under which they were 

 formed, became such as to admit of their preservation in the 

 order in which they now appear, whether by gradual alteration 

 of level or otherwise. That the change from one series of 

 deposits to the other was gradual, we may surely infer from an 

 inspection of this Section, At the close of the epoch marked 

 by the deposition of the vast masses of Marls and Conglomerates, 

 characterized by the presence of peroxide of Iron as the 

 colouring matter of their minute particles, we see that detrital 

 deposits were introduced from other sources, in which colour, as 

 derived from Iron, was nearly if not entirely absent. Yet the 

 original source of the bulk of the " Old Eed " formation had 

 not been entirely exhausted, but was still subject to periodical 

 breakings-up and re-deposit, as we may see in the occasional 

 recurrence of red beds, not differing in Uthological character 

 from those far beneath them, which subsequently attain to their 

 fullest development in the Grits of the Coal measures, and finally 

 supplement them. The Encrinite, which appears in the layers 

 indicated as fossiliferous, is the Adinocrinus triacoiitadactylus. 

 None of the beds, other than those especially indicated, so far 

 as we observed in our ctirsory inspection of them, contained any 

 fossils. No period of geological time seems to have been more 

 distinctly characterized by the action of disturbing forces, than 

 that of the close of the Carboniferous system, and this disturbing 

 force has apparently been much greater upon those parts of the 

 continent known to me, than in ovu' own district. I send with 

 the present notes, for the service of such members of the club 

 as may be inclined to make use of them, the admirable Sections 

 of the corresponding beds in Belgium, and the " Essai d'une 

 Carte Geologique des Environs de Dinant," given to me by my 

 friend Dr. Edotjakd Dupont, of that place. 



John Jones. 



