AUSTEN — EXTENSION OF THE COAL-MEASURES. 49 



the included fossils would be easily separable, rather than of the com- 

 pact flat-bedded limestones of the valley of the Vesdre. The destruc- 

 tion of such beds as those about Stadkyll and Gerolstein would pro- 

 duce just such a conglomerate as that of Malmedy. 



If then we restore the whole of this area to its original position, 

 we find, with reference to submarine conditions, that the Stringoce- 

 phalus-limestone group on the Eifel side presents a great development 

 of marine forms which lived there, whilst they diminish in the direc- 

 tion of the Vesdre beds, and it is also in this direction that the 

 mineral character of the limestone group changes, and passes into 

 shales, — this takes place from south to north. 



The distribution of sedimentary matter being dependent on the 

 moving power of water, and on the specific gravity of the materials 

 moved, such conditions as those here indicated inform us that the 

 land side of such an area of water must have been to the north of the 

 group of deposits in question. 



Again in the next subjacent group — that of which the conglomerate 

 of Burnot forms a subordinate part, we meet with the clearest evi- 

 dence of its relation to an old coast-line. The whole mass of this 

 conglomerate is littoral shingle or gravel : along the valley of the 

 Vesdre, it is some twenty feet in thickness : it is somewhat less in 

 the wood of Stanu : in the Eifel country it has lost its marginal 

 character and become a sandstone, — a change which marks the out- 

 ward extension of the sea-bed to have been for this zone what it was 

 for the limestone group — or from north to south. 



With reference to the Bellignies section, the differences which this 

 group there presents consist in the greater coarseness of the materials 

 of the Cailloux du Diable, together with a greater thickness of the 

 conglomerates and sandstones ; where it rises again to the south, near 

 Mondrepuis, its composition is not so coarse, being made up of small 

 lenticular shingle, with thick beds of coarse sands. This conglomerate 

 band again rises on the north of the Mons coal-basin ; the distance 

 between these extreme points gives forty miles for the width of the 

 zone of marginal sea-bed here ; as in former instances, the gradation 

 in composition shows that the passage from coarse to finer sea-bed 

 takes place from north to south. 



Lastly the extension of a mass of shingle along a line 120 miles in 

 extent, from near Valenciennes to beyond Eupen, is wholly in- 

 explicable except under the supposition, that it marks the direction 

 of old marginal and submarginal zones of sea-bed. 



The limestones of the right bank of the Rhine, near Dusseldorf, 

 are a prolongation of those of the valley of the Vesdre, and indicate 

 similar conditions ; but in the underlying group the conglomerate 

 band disappears, and is represented by a sandstone series. The 

 interval of the valley of the Rhine may be taken at about 35 miles, 

 so that in a north-east direction there is a mineral change such as 

 takes place in the south-east. 



The line along which these data have been taken, and which 

 trends irregularly east and west, shows with respect to certain beds, 

 of which the mineral character affords definite indications, that at 



VOL. XII. — PART I. E 



