SUPERIOR SANDSTONES. 421 



seen ; and it may serve to prove, that where sand 

 and sandstone are found intermixed, the former 

 is as likely to have originated in the disintegra- 

 tion of the latter, as that the rock has been con- 

 solidated from loose sand. 



With respect to the supposed veins of white 

 sandstone, it is unnecessary to say more than what 

 was remarked in speaking of similar occur- 

 rences in the red. Whatever the nature of such 

 appearances may be, they can only be consi- 

 dered as veins by ignorance or voluntary self- 

 deception. 



The structure of the sandstones under review, 

 is almost invariably fine grained and arenaceous, 

 like the predominant varieties of the red and 

 lowest strata. They rarely afford examples of a 

 conglomerate or coarse grained structure. They 

 vary however materially in point of induration ; 

 being sometimes extremely tender, and, at others, 

 compacted to the hardness of quartz rock. In 

 some rare instances, they are as compact as the 

 most crystalline varieties of that rock ; but, in 

 these, it will generally be found that they lie in 

 the immediate vicinity of trap, to the influence 



