252 Elie de Beaumont's Rcscan-hcs on some of 



system, distinguished by the N.W. and S.E. direction of the 

 greater part of its ridges and valleys, and by the beds of the 

 red or variegated sandstone {grcs biga?-re), the muschelkalk, 

 and the variegated marls {marncs irisces) being throv/n out of 

 their original position, as well as all the more ancient rocks. 

 In the centre of France, near Avallon and Autun, the granitic 

 and porphyritic protuberances of Morvan stretch from N.W. 

 to S.E., disturb the coal-measures, and raise a peculiar arkose, 

 contemporaneous with the variegated marls, to their summits; 

 whilst the lias and another arkose, which forms its lowest part, 

 extend horizontally to the feet of the same protuberances and 

 form the plains which surround them. The same direction, 

 and in part the same geological circumstances, are observable 

 in the hills, partly granitic, of the S.W. coast of Britanny and 

 La Vendee. These circumstances also appear in that part 

 of the Bohmerwaldgebirge which separates Bavaria from Bo- 

 hemia, in the Thuringerwald, and in the lines of disturbance 

 in the muschelkalk and the variegated marls (keuper) which 

 according to the excellent map of M. Hoffmann run in the 

 same manner from S.E. to N.W. across the nearly flat coun- 

 tries situated between the Hartz and the Taunus. It therefore 

 appears that the elevation of the different parallel chains above 

 mentioned, is referrible to that revolution on the surface of 

 the globe to which the sudden difference observable between 

 the variegated marls and the lias is due. 



VII. Si/stem of the Pilas, the Cote (POr, and of the Erzge- 

 lirge. — Professor Sedgwick has summed up, in his last Address 

 to the Geological Society of London, our knowledge respect- 

 in"- this system. It includes (in Eastern France) the higher 

 elevations of the Cote d'Or and Mont Pilas, the Cevennes, 

 and a portion of the Jura chain. It may be traced towards 

 the valley of the Rhine, where it is suddenly cut off; but it re- 

 appears in the chain of the Erzgebirge, between Bohemia and 

 Saxony. It never rises into mountains of the first order, but 

 is marked throughout (as may be seen on a good physical map) 

 by many longitudinal ridges and furrows, ranging nearly pa- 

 rallel to each other in a direction about north-east and south- 

 west. So far the statement is only an enumeration of certain 

 connected facts in physical geography. But it is followed by a 

 coordinate series of geological phEenomena. 



A number of formations, including in the ascending order 

 the whole oolitic series, enter here and there into the compo- 

 sition of the geographical system above described ; and, with- 

 out exception, wherever they appear all are in turn elevated, 

 broken, or contorted ; yet in their lines of range they pre- 

 serve a parallelism to the general direction of the ridges. On 



the 



