21 



way down the declivity. The author is of opinion that tlie coal- 

 measure ranges uninterruptedly from Coalbrookdale to the Abber- 

 ley Hills. The greater part of the workings are only shallow pits, 

 touching merely the sulphureous beds, locally called " stinkers." 



The upper portion of the measures is chiefly composed of sandy^ 

 micaceous, thinly bedded loamstone with vegetable remains, sand- 

 stone and quartzose conglomerate; the middle and lower part, in 

 which the coal is chiefly wrought, of slate clay, micaceous loamstone, 

 sandstone grit and calcareous conglomerate. Abundance of ve- 

 getable remains are found in the shale, but no other fossils. 



The author states that this coal-field is peculiar in the constant 

 occurrence of a calcareous conglomerate called cornstone. He says 

 it is seen in different parts of the series, sometimes at the top, as at 

 Glazeley, and sometimes in the middle, forming a concretionary 

 limestone. The lowest of the coal strata are described as being 

 more indurated than the upper, and as consisting of brown and grey 

 sandy loamstone, and coarsely laminated flagstone grits, with thin 

 layers of conglomerate of a deep chocolate colour. The author 

 then briefly alludes to the base of the coal-measures or the old red 

 sandstone, and to the intrusive rocks, which he says abound on every 

 side of the great south Shropshire coal-field. 



A paper was lastly read " On a Freshwater Formation contain- 

 ing Lignite in Cerdagne in the Pyrenees/' by Charles Lyeli, Esq., 

 Foreign Sec. G.S. 



The upper part of the basin of the river Segre in Cerdagne pre- 

 sents an example, rare in the Pyrenees, of a great longitudinal valley 

 running east and west, or nearly parallel to the axis of the chain. 

 This basin is formed by a depression in the central region of granitic 

 rocks, which, in the eastern division of the Pyrenees is of consider- 

 able breadth. The lacustrine strata occupy the lower f)arts of the 

 depression, reposing horizontally on the granite, hornblende schist 

 and argillaceous schist. The breadth of the freshwater formation 

 is about five miles, and its elevation above the sea probably between 

 three and four thousand feet. Its eastern limits are seen to the east- 

 ward of Livia, where the boundary is formed by the ridge of granite 

 from which the head waters of the Segre descend. At this outcrop 

 the freshwater clays are seen to be covered with beds of such gravel 

 as might now be supplied from the waste of the surrounding moun- 

 tains of granite and schist. On crossing the ridge of granite from 

 the basin of Segre to that of the Tet, the author found no recur- 

 rence of the freshwater strata in the valley of the last-mentioned 

 river. The northern outcrop of the lacustrine deposit is well seen 

 at Ur, between Porte and Puycerda, where the strata consist chiefly 

 of coarse gravel resting on highly inclined hornblende schist. The 

 deposit is for the n)ost part composed of variously coloured clays, 

 often laminated, in which shells of the genera Limneus and Planor- 

 bis abound, as at Estavan, near Livia, in French Cerdagne, where 

 lignite has been worked, and where there are bituminous clays con- 

 taining impressions of plants. Lignite is still procured from pits at 

 Prats, near Senabastre, in Spanish Cerdagne. 



