SECONDARY ROCKS—GENERAL RELATIONS. 21 



deposit of an understood geological age occurs, still we are 

 not to consider that these far separated deposits must neces- 

 sarily be of the same age. That they may be, is possible, but 

 it is as probable that they may not, and their evidence is 

 never to be opposed to that affordedby superposition. 



That the red conglomerates and sandstones of the Lo- 

 thians are not derived from the consolidation of sands and 

 rolled masses brought from a great distance, is apparent, 

 from the fact that no rock-fragments are found in them, 

 but such as occur in situ in their more immediate neigh- 

 bourhood. That vast deposit of red sandstone conglo- 

 merate which skirts continuously the Greywacke formation 

 of the Lammermuirs, from Redheugh in Berwickshire to 

 Heartside in Haddingtonshire, and which rises into moun- 

 tain masses in several parts, is entirely composed of variously 

 shaped rolled masses of greywacke and transition-slate. Be- 

 sides containing masses of the stratified or Neptunian rocks, 

 on which the conglomerates rest, they also, though rarely, 

 include rolled masses of members of the felspar series. 

 In the red sandstone hill of Chesters, near the village 

 of Spott in East Lothian, masses of felspar-porphyry 

 occur, and, in the conglomerates of Carlops and Hab- 

 bie's How, fragments of compact felspar are abundant. 

 These appearances therefore indicate that all the mem- 

 bers of the felspar series of the Lothians are not newer 

 than the carboniferous formations ; but prove, on the con- 

 trary, that by being subjected to aqueous attrition, they 

 have contributed to the formation of these strata. The 

 white sandstone series, which alternates with the red, and 

 has been entitled The Independent Coal Formation, is, like 

 the red sandstone, compound ; it is an assemblage of white 

 sandstones, slate-clay, bituminous shale, clay ironstone, and 

 coal. In the Red Sandstone series, the sandstone is in ge- 



