The whin-stone of Scotland is also the same with the toad-stone of Derbyshire, which is of the amygdaloides species; it is also the same with the flagstone of the south of Staffordshire, which is a simple whin-stone, or perfect trap.  England, therefore, must be included in this great space of land, the mineral operations of which we explore; and also Ireland, of which the Giant’s Causeway, and many others, are sufficient proof.

In the south of Scotland, there is a ridge of hills, which extends from the west side of the island in Galloway to the east side in Berwickshire, composed of granite, of schistus, and of siliceous strata.  The Grampians on the north, again, form another range of mountains of the same kind; and between these two great fields of broken, tumbled, and distorted strata, there lies a field of lesser hardness and consolidation, in general; but a field in which there is a great manifestation of subterraneous fire, and of exerted force.

The strata in this space consist, in general, of sand-stone, coal, lime-stone or marble, iron-stone, and marl or argillaceous strata, with strata of analogous bodies, and the various compositions of these.  But what is to the present purpose is this, that, through all this space, there are interspersed immense quantities of whinstone; a body which is to be distinguished as very different from lava; and now the disposition of this whin-stone is to be considered.

Sometimes it is found in an irregular mass or mountain, as Mr Cronstedt has properly observed; but he has also said, that this is not the case in general.  His words are:  “It is oftener found in form of veins in mountains of another kind, running commonly in a serpentine manner, contrary or across to the direction of the rock itself.”

The origin of this form, in which the trap or whin-stone appears, is most evident to inspection, when we consider that this solid body had been in a fluid state, and introduced, in that state, among strata, which preserved their proper form.  The strata appear to have been broken, and the two correspondent parts of those strata are separated to admit the flowing mass of whin-stone.

A fine example of this kind may be seen upon the south side of the Earn, on the road to Crief.  It is twenty-four yards wide, stands perpendicular, and appears many feet above the surface of the ground.  It runs from that eastward, and would seem to be the same with that which crosses the river Tay, in forming Campsy-lin above Stanley, as a lesser one of the same kind does below it.  I have seen it at Lednoc upon the Ammon, where it forms a cascade in that river, about five or six miles west of Campsy-lin.  It appears to run from the Tay east through Strathmore, so that it may be considered as having been traced for twenty or thirty miles, and westwards to Drummond castle, perhaps much farther.