288 Geological Society. 



the North of England seldom exists but as a conglomerate, and is 

 seen in that form on the flanks of the Cheviot Hills) with the red 

 beds of mountain-limestone and sandstone, which, both in Cumber- 

 land and Lancashire, sometimes form the base of the whole carbo- 

 niferous series. 



Such are the remarkable changes of our carboniferous system in 

 its range from the Bristol Channel to the Scotch border : and it re^ 

 appears on the north-side of the great greywacke chain of that country 

 with so many points of analogy, that we must, i think, regard the 

 coal measures in the neighbourhood of Edinburgh as part of a 

 very ancient deposit, nearly of the same age with that on the banks of 

 the Tweed*. 



Thus it appears, from what has been stated above that tree 

 ferns, gigantic equiseta, and other plants belonging to the herba- 

 rium of the ancient coal-fields, grew on the land, and were some- 

 times swept down into the sea, before the elevation of the grey- 

 wack chains of one portion of the British Isles that in after times, 

 the same families of plants were swept down into the sea, in immense 

 abundance, and spread out, here and there, in beds alternating 

 with mud, sand, and banks of zoophytes and sea-shells, during the 

 whole period of the deposit of mountain-limestone, from its beginning 

 to its end lastly, that these mechanical accumulations continued 

 to go on in shallow seas and estuaries (and perhaps also in inland 

 lakes), till the whole process of degradation was interrupted by the 

 elevation of the carboniferous chain, producing the enormous breaks 

 and dislocations above described, and succeeded by the conglomerates 

 of the new red sandstone. 



Before I leave this subject, 1 may notice a work, just published by 

 Mr. Witham of Edinburgh, containing many beautiful illustrations of 

 the internal structure of fossil plants derived from the old coal-fields 

 of the Tweed, and from various parts of Scotland. By submitting 

 extremely thin, polished slices of these fossils to microscopic observa- 

 tion, he has been enabled to detect the minutest traces of organic 

 texture -, and he has proved the existence of so large a number of 

 phanerogamic plants, in the lowest part of the carboniferous series, 

 as greatly to modify one of the positions laid down in the Prodromus 

 of M. Adolphe Brongniart. 



A paper, by Dr. Buckland and Mr. de la Beche, on the Geology of 

 Weymouth and the adjacent parts of the coast of Dorsetshire, brought 

 before us all the secondary deposits of this island, from the lower divi- 

 sion of the oolites to the chalk. It is so rich in its details, and adorned 

 with such admirable illustrations, that the structure of the whole 

 region, though crowded with formations, dislocated, contorted, and 



* The general relations of the various groups of the carboniferous system of 

 Northumberland, are, on the whole, very faithfully represented in the geological 

 map of that county, published some years since by Mr. Smith. A very detailed 

 description of a portion of the carboniferous series of the Tweed was read during 

 the past year, by Mr. Winch, before the Philosophical Society of Newcastle, and 

 has been since published. [See our present volume, p. 11. EDIT.] Another 

 paper, on the same subject (which I did not see till these sheets were passing 

 through the press), has been recently published by Mr. Witham of Edinburgh. 



traversed 



