2*28 UPPER SANDSTONES. 



or ferruginous, or all together, presenting endless va- 

 riations of aspect and colour. If red hues prevail, it 

 is sometimes also brown, yellowish, grey, greenish, 

 and even white ; and is often singularly striped and 

 spotted with different colours, whence its name of varie- 

 gated. We must be cautious, however, of deciding on 

 the geological position of a sandstone from this circum- 

 stance, as has been often done ; since I have shown 

 that it occurs in the " old" red sandstone also. Further, 

 it contains fetid and oolithic, as well as common lime- 

 stones, in some places ; though the minuter details must 

 be sought in the numerous works of authors. 



But that which especially distinguishes this deposit 

 from all the secondary sandstones, is the presence of 

 rock salt. If not thus absolutely limited, gypsum 

 also occurs in it, so as to become another characteristic. 

 But it is the proper, or even exclusive repository of 

 salt, although that mineral occasionally passes beyond 

 the rigid boundaries, on both sides, so as to appear in 

 the magnesian limestone below it, and in the lias above; 

 as noticed in the chapter on that substance. 



With respect to its organic remains, their presence 

 has sometimes been denied ; but there seems no doubt 

 of the fact as to the foreign examples. On the con- 

 tinent, there have been found remains of lacertae and 

 fishes, with gryphites, ammonites, and belernnites ; 

 while the vegetable fossils are said to amount to twenty 

 or more, comprising equisetums and ferns, like the 

 coal-strata, with some coniferous and liliaceous plants, 

 as well as fuci in the lower portions ; if indeed some 

 or all of these do not rather belong to the strata in 

 contact, with which it has been confounded, or to 

 fresh water formations not sufficiently distinguished 

 from it. In England, it has been said that no organic 

 remains occur in the proper red marl. 



