222 A POPULAR SKETCH OK THK 



sandstone itself was also precisely the same. Although, then, I 

 have not seen the place myself, I have little doubt of its being in 

 the upper part of this formation. 



Near the borders of Nottinghamshire, at Sandiacre and Stapleford, 

 there are some very thick beds of a dark red sandstone, containing 

 lines of pebbles, which I believe to belong to the lower part of the 

 red and white sandstones, but of which I am not yet certain. 

 There are one or two hundred feet of them exposed, forming sonic 

 rather bold hills. The stone is hard and coarsegrained; but the 

 pebbles are hardly in sufficient number to give the rock the name of 

 a conglomerate. 



The next rock in order below the red and white sandstones, is 



4. — The Magnesian Limestone. 



Like all the other portions of the new red sandstone, this rock, 

 while it preserves some characters, varies greatly in others in diffe- 

 rent parts of its range. When it occurs in Derbyshire, it is in its 

 upper parts a beautiful white freestone, sufficiently soft to be cut 

 with a knife, with a sparkling crystalline texture like coarse-grained 

 loaf sugar. This is its character at Streetly wood, where it is thick 

 bedded and quarried to a considerable extent. In other places it is 

 thick bedded, harder, and more compact, and of a light yellow or 

 straw colour. Some portions, while preserving this light colour and 

 compactness, are thin bedded and flaggy, and much jointed ; others 

 again are in coarse-grained rough flags of a brick-red colour. Its 

 lower portions are generally yellowish-brown, sometimes flaggy, 

 and sometimes occurring in very smooth regular beds about a foot 

 in thickness, when it is quarried for building stone. Its lower parts 

 likewise contain sometimes beds of carbonate of lime, of a dull blue 

 colour. Few or no fossils are anywhere found in this formation in 

 Derbyshire : when they do occur they consist of marine shells. 

 The thickness of this rock probably exceeds 300 feet. Below it, is 

 sometimes, but not always, seen 



5. — The Lower Red Sandstone. 



This lowest portion of the new red sandstone system is still more 

 variable in its characters than any other part. Its general charac- 

 ter is that of a hard compact stone of a light red colour. It is, 

 however, sometimes a soft micaceous sandstone, sometimes contains 

 beds of red marl, and sometimes is indistinguishable in appearand 



