42 Lord Greenock on the Igneous Rocks 
ably and correctly executed by Dr Greviize, F.R.S. Ed., than 
by any written description (See Plate). The first appearance of 
disturbance commences to the eastward of the limits of the 
drawing in that direction, and about 200 yards from the point 
of junction between the secondary rocks and the trap, where the 
former may be observed to rise at an angle of about 11° or 
12° above the level of the road, crossing a footpath that leads 
up the declivity. Owing, however, to the partial covering 
of soil and vegetation, several of the strata can be traced only 
here and there, by their edges cropping out. There appear to 
be about five or six strata of sandstone in all, varying in thick- 
ness from two or three feet to a few inches, the intervals between 
them being occupied by beds of slate-clay, or perhaps of marl, 
of a reddish-brown or purple colour; but in their present state, 
neither the continuity of the one, nor the nature of the other, 
can be distinguished with any accuracy. 
The irregularity and want of conformity in the stratification 
of these rocks, and the curvatures observed in them, are very re- 
markable, giving such strong evidence, that, whatever the cir- 
cumstances might have been which influenced their original de- 
position, they must subsequently have experienced a considerable 
derangement, as to leave no doubt in the author's opinion, that 
the signs of disorder so manifestly visible in this section, are to 
be attributed to some subterraneous agency. In this view, the 
only rational explanation that occurs to him is, that they were 
occasioned by that general disturbing cause, which probably act- 
ed upon a large extent of country at the period when it was ele- 
vated above the waters, beneath which it had been originally 
formed. Considering the subject, therefore, in this light, it ap- 
pears probable that the whole of the sandstone strata, with the 
intervening beds of slate-clay or marl, had, on the first impulse 
they received during the process of elevation, a tendency to rise 
in a uniform direction ; but, in consequence of some violent dis- 
turbance that must suddenly have interrupted the regularity of 
