in the Neighbourhood of Edinburgh. 255 



But, when alternations of coal are included in our considera- 

 tion, still more complicated views arise. 



Coal has arisen from the decay of vegetables which grew 

 on the spot ; generally in marshy sites, or in shallow waters. If, 

 then, we find seams of coal alternating with sandstones, shales, or 

 limestones of a fresh-water origin, no inference remains, but that 

 oscillatory movements of the earthy crust must have taken place, 

 by which land became submerged beneath the surface of a fresh- 

 water lake, from which, by a subsequent elevation of the land, it 

 has emerged, so as to give rise to a new Flora. And, in the case 

 of coal-seams alternating with limestones of marine origin, which 

 is also incidental to the coal-field of Mid-Lothian, a similar in- 

 ference arises, that dry or marshy land had become submerged be- 

 neath marine waters, and had again arisen from the bosom of the 

 deep, to be decked with a new flora, and with fresh verdure. 



While all these inferences are suggested by the system of 

 strata which I have described, there are still other important cir- 

 cumstances to be taken into consideration. 



These alternations of elevation and depression have, in the 

 coal-fields of Scotland, been conducted with a freedom from dis- 

 turbance which is most remarkable. In few instances, except 

 where local eruptions of trap-rock have prevailed, have I found 

 derangements of strata marking the junction of marine and flu- 

 viatile deposits, or any intervening conglomerate strata, from 

 which diluvial effects might be inferred. Near Bathgate, a lime- 

 stone of marine origin may, at its junction with a fluviatile bed, 

 be found to actually graduate into a fresh-water deposit. While 

 the great mass of the rock encloses encrinites, corallines, &c, the 

 unio appears in its uppermost bed, near its junction with an over- 

 lying bed of sandstone, filled with the remains of plants. East 

 of Dunbar, also, no marks of violence whatever characterise the 

 junction of two rocks, where, in the compass of a few inches only, 

 we find the encrinites of a bed of limestone, abruptly, though 

 quietly, overtopped by a sandstone containing calamites. 



