708 



GEOLOGY. 



the different tints of the marls, the groups have been called Poikilitic by Mr. Conybeare, 

 signifying mottled or varied ; and Saliferous salt-bearing by others, from the immense 

 deposits of rock-salt. But the New Eed Sandstone is the appellation in most common use, 

 denoting the arenaceous composition of the predominant rocks, the colour prevailing in 

 the suite, and its more recent date than the Old Red Sandstone, which underlies the car 

 boniferous system. Argillaceous, calcareous, magnesian, and saline strata marls, lime 

 stone, magnesian limestone, and rock-salt, are variously associated with the sandstone. 



Where the series is completely exhibited in England, it presents the following succession 

 of beds : 



'Variegated marls. Eed, with bluish, greenish, and whitish laminated clays or marls, holding 

 Upper, or gypsum generally, and rock-salt partially, as in Cheshire. Included in these marls are 

 Triassic certain white and grey sandstones. 

 System. Variegated sandstones. Red sandstones, with some white and mottled portions, the lower 



parts in some districts (Nottinghamshire) pebbly. 

 'Laminated limestones of Knottingley, Doncaster, &c., with layers of coloured marls, 30 or 40 



feet. 



Gypseous marls. Red, bluish, and mottled. 



Lower, or Magnesian limestone, yellow and white, of various texture and structure, some parts full of 

 Permian - fragmentary masses. 

 System. Marl slates. Laminated, impure, calcareous rocks, of a soft argillaceous or sandy nature. 



Red sandstone, with red and purple marls and micaceous beds. The grits are sometimes 

 white or yellow, and pebbly. When conformable, this sandstone occasionally passes into 

 the coal-measures on which it rests. 



It is only in a few places in the north of England that the above beds are found entire. 

 In other parts of the kingdom, as well as on the continent, several members are wanting, 

 and sometimes the whole series is almost exclusively represented by the gypseous marls, 

 or the magnesian limestone, or the red mottled sandstone. The following table exhibits 

 the complete German, English, and French series : 



Germany. 



England. 



France. 



Keuper marls and grits. Keuper is supposed 

 to be a German miner's term ; but the deri 

 vation is unknown. 



Muschelkalk a limestone so denominated 

 from its containing an abundance of mollus 

 cous remains. 



Bunter sandstein mottled sandstone, a name 

 which originated with Werner. 



Stinkstein, fetid limestone; Rauwacke, cel 

 lular limestone. 



Gypseous marls - 



Zechstein mine-stone, referring to veins of 

 copper ore being found in it. 



Kupfer schiefer copper-slate 



Rothe-todte-liegende red dead-lier, indi 

 cating that the metallic ore in the above 

 deposit has died out, and is not found in 

 the underlying red sandstone. 



Variegated marls and white and grey 

 grits. 



Variegated sandstones 

 Upper limestone. 



Gypseous marls. 

 Magnesian limestone. 



Marl slate. 



Lower red sandstone 



Marnes Irisees. 

 Muschelkalk. 

 Gres bigarres. 



Gres do Vosges. 

 Gres rouge. 



It will be seen from a comparison of the above table, that the German series differs 

 from the English in the addition of the muschelkalk ; while the French contains it, and 

 differs from that of the other two countries in the absence of various beds. It has, there 

 fore, been remarked, as an important fact for the student to bear in mind, that it is by a 

 general analogy in the type, and not by any conventional series of strata, that systems 

 are to be identified in different countries. In France, the chain of the Vosges a ridge 

 which separates the ancient province of Alsace from that of Lorraine, and stretches 

 northwards into the Bavarian circle of the Rhine consists of granite and primary strata. 



