396 LOWEST RED SANDSTONE. 



fore considered merely in the light of alternating 

 strata, and are separated accordingly, so as to 

 come under examination in their proper place. 



When the red sandstone under review is pre- 

 sent, it is in contact, at its lower part, with the 

 primary strata ; and, thus, may approximate to 

 any one of the whole series formerly described. 

 It is rarely found so situated with respect to 

 granite ; but Kildrummie in Aberdeenshire, and 

 Sutherland, furnish examples of this nature. It 

 is also more frequently found in contact with the 

 argillaceous schists, than with the other members 

 of the primary class; although it does occur in 

 this manner with every one of them. As it is, 

 however^sometimes absent, other members of the 

 secondary strata are found occupying the lowest 

 position. 



It was already noticed in the preceding chap- 

 ter, that the strata of this sandstone are not neces- 

 sarily placed in a reverse, or unconformablc 

 order, to the primary with which they are in 

 contact. In certain cases, they are found to suc- 

 ceed them in a parallel position ; and, in these, 

 when argillaceous schist is the preceding rock, it 



