in the Neighbourhood of Edinburgh. 237 
Lastly, during the tremulous efforts by which lines of fracture 
have been made to approximate, igneous matter has not unfre- 
quently intruded itself through these fissures. ‘Thus we may 
conceive a large fissure through which trap has protruded, to 
be indicated by the eruptions, continued with little interrup- 
tion, which we trace from Tinto to the Pentlands, and thence 
to Salisbury Craigs, in a direction of nearly §. W. to N. E. 
From these observations it would appear, that the carbonife- 
rous strata under our consideration shew striking marks of the up- 
heavings and the rents which they have undergone both before 
and subsequent to the completion of their deposit, accompanied 
with eruptions through them of plutonic rocks. In conse- 
quence of these rents, and of the uplifting power which has been 
exerted along the line of them, the coal-fields of Mid-Lothian 
have been broken up into various systems of strata, severally dif- 
fering from each other in the extent of the beds which have been 
made to emerge. This difference would naturally be in confor- 
mity with the circumstances under which the uplifting force has 
exerted its influence. 
In examples where the anticlinal energy has acted powerfully 
at one and the same time upon a great extent of surface, we find 
that at the line of rent or fissure very deep-seated beds have been 
made to emerge, or crop out :—as may be shewn on the coast of 
North Berwick and among the Pentlands, by the emergence of 
beds even inferior to the carboniferous group. But examples are 
far more numerous of the line of fracture being distinguished by 
the cropping out of no deeper seated beds than those of a ma- 
rine limestone, to which I have given a middle place in the car- 
boniferous system to which the limestone of Burdiehouse belongs. 
The systems of strata, separated from each other by lines of 
fissure which are in greater or less contiguity with the limestone 
of Burdiehouse, I shall now explain in reference to the following 
section. 
