SUCCESSION AMONG ROCKS. 295 



followed by a series of coal strata or lignites, already 

 noticed, as found in Sutherland, and which also im- 

 mediately rests on the granite. 



A great part of the middle district, also, consists 

 solely of the lowest sandstone ; and the remainder 

 presents a series of coal strata succeding to that. As, 

 in some places, a limestone is interposed between 

 these strata and the lowest sandstone, analogous to 

 the lowest or mountain limestone of the English, it 

 may be fairly considered that there is a perfect 

 analogy between this deposit and that of England as 

 far as it extends. But that extent is limited ; since, 

 in many places, this limestone is wanting. Hitherto, 

 with some rare exceptions, the coal strata have been 

 found to reach the surface everywhere in this tract ; 

 neither the magnesian limestone, which follows in 

 England, nor the red marl stratum, forming a part 

 of the series. Nor are any of the strata that lie 

 above those found in it, whatever slender indications 

 there may be ; so that the chief Scottish secondary 

 series, even where most complete, terminates with the 

 coal deposit. 



The Western secondary deposit is rendered very 

 obscure by its scattered and disturbed position, and 

 by the very limited quantity of it which exists. In 

 some places, as at Campbelltown, it exhibits the 

 lowest sandstone, while in others, as in Morven, 

 that is wanting ; the lias, with the coal, or lignite* 

 reposing immediately on gneiss. In some also, there 

 is an inferior limestone ; but, however connected with 

 the lias, it appears, in its relation and in its cha- 

 racters and fossils, to correspond to the mountain 

 limestone of England. The actual coal series where 

 it exists, is very limited, and must be considered to 

 belong to the first coal which follows the great coal 



