With this view I have often considered our schistus mountains, both in the north and south; but I never found any satisfactory appearance from whence conclusions could be formed, whether for the question or against it.  The places I examined were those between the alpine countries and the horizontal strata; here, indeed, I have frequently found a confused mass, formed of the fragments of those alpine strata mixed with the materials of the horizontal bodies; but not having seen the proper shape and connection of those several deposits, I always suspended my judgment with regard to the particular operations which might have been employed in producing those appearances.

I had long looked for the immediate junction of the secondary or low country strata with the alpine schistus, without finding it; the first place in which I observed it was at the north end of the island of Arran, at the mouth of Loch Ranza; it was upon the shore, where the inclined strata appeared bare, being; washed by the sea.  It was but a very small part that I could see; but what appeared was most distinct.  Here the schistus and the sandstone strata both rise inclined at an angle of about 45 deg.; but these primary and secondary strata were inclined in almost opposite directions; and thus they met together like the two sides of a lambda, or the rigging of a house, being a little in disorder at the angle of their junction.  From this situation of those two different masses of strata, it is evidently impossible that either of them could have been formed originally in that position; therefore, I could not here learn in what state the schistus strata had been in when those of the sand-stone, &c, had been superinduced.

Such was the state of my mind, in relation to that subject:, when at Jedburgh upon a visit to a friend, after I had returned from Arran, and wrote the history of that journey; I there considered myself as among the horizontal strata which had first appeared after passing the Tweed, and before arriving at the Tiviot.  The strata there, as in Berwickshire, which is their continuation to the east, are remarkably horizontal for Scotland; and they consist of alternated beds of sand-stone and marl, or argillaceous and micaceous strata.  These horizontal strata are traversed in places with small veins of whin-stone, as well as greater masses forming rocks and hills of that material; but, except it be these, (of which there are some curious examples), I thought there could be nothing more of an interesting nature to observe.  Chance, however, discovered to me what I could not have expected or foreseen.

The river Tweed, below Melrose, discovers in its bed the vertical strata of the schistus mountains, and though here these indurated bodies are not veined with quartz as in many places of the mountains, I did not hesitate to consider them as the same species, that is to say, the marly materials indurated and consolidated in those operations by which they had been so much changed in their place and natural position.  Afterwards in travelling south, and seeing the horizontal softer strata, I concluded that I had got out of the alpine country, and supposed that no more of the vertical strata were to be observed.