GRANITE. 91 



is so common, that I need only quote the examples of ,. 

 Cornwall and the South of Scotland ; and the passage ^ ^ ^ 

 of veins through the schist is equally well known. I ^ . 

 need not notice the other primary strata, since, as far as ,^ 

 their geological relations are concerned, they are all 

 implied in those now enumerated ; hut it is apparent 

 that granite is, or may be, posterior to the whole mass 

 of the primary series, as it is, somewhere or other, 

 more recent than every memher of it. 



The only instances known to me of the contact of' 

 granite with the secondary strata, are those which I 

 have discovered in Scotland, elsewhere noticed. In 

 Caithness and Sutherland, the lowest red sandstone in 



/ . .TT , - ' .' 



one place, and the series of the lias and oolithe with 

 coal in another, reposes on the same mass, so that 

 every member in a very extensive deposit, is in 

 contact with a granite, which in other places, is in si- 

 milar contact with gneiss, quartz rock, and micaceous 

 schist. Thus the possible proximity of granite to every 

 secondary stratum is proved ; since there is no reason 

 why it should not extend higher up in the whole se- 

 ries. There are here however no marks of intrusion: 

 so that these strata have been deposited on the gra- 

 nite and its accompanying primary strata, at the same 

 period. Yet this fact proves the antiquity of the 

 granite in question : since it must be more antient 

 than that which elevated the primary and secondary 

 strata together, and which seems never to have intruded 

 among the latter, unless it has done this under the 

 form of trap, so utterly incapable of disentanglement 

 from granite in these cases. 



If I have rejected the case of granite reposing on 

 the secondary strata, referring it to the Trap family, 

 by the definition, yet as others may choose to consider 

 the mineral character as constituting granite, in what- 



