in the Neighbourhood of Edinburgh. 43 
this movement, a considerable fault or dislocation was occasioned 
towards the centre of the section, by which they became bent 
and distorted in the manner now seen,—their eastern portions 
having been thrown up, whilst their western portions were cast 
down, so as to lie unconformably upon the upturned strata. Near 
the point of junction of these rocks with the trap, the effects of 
subsidence are very evident, the shattered extremities of the 
strata having apparently fallen over, being at the same time forced 
into a more southerly direction, by which they seem to have been 
brought obliquely into contact with the tabular masses of green- 
stone, against which they appear to have been precipitated, and 
upon which the inverted fragments of sandstone, with interven- 
ing portions of slate-clay or marl, are now seen to rest. 
If the trap had been in a soft state from fusion at the time, 
some intermixture of the igneous fluid with the stratified rocks 
must have taken place during this collision; but no imbedded 
fragments are to be met with, nor any veins passing from the one 
into the other ; neither are there any marks or impressions visible 
on the smooth surface of the greenstone, except some slight su- 
perficial scratches, such as might have been caused by abrasion 
during the simultaneous passage upwards of these two descrip- 
tions of rocks, if both had been consolidated previous to their 
elevation. The fragments, however, imbedded in the upper part 
of the rock, as well as the altered nature of some of the contigu- 
ous strata, shew that, at some period, this rock must have been in 
a state of fusion, and capable, by its intense heat, of affecting, in 
this manner, the stratified rocks in its vicinity. 
Although at first sight it might appear difficult to reconcile 
these opposite and apparently contradictory facts, if we can ad- 
mit that the stratified rocks had been deposited in seas or lakes, 
and that the trap had also a subaqueous origin, it must follow 
that the dry land which they now form, must, at some time or 
other, have been elevated above the waters, when, in all probabi- 
lity, a considerable modification of their relations with each other 
F2 
