and was full of bivalves with the impressions as strong as in a common secondary limestone.  The strata on both sides had the same inclination, and were decidedly primary, consisting of the ordinary micaceous schistus.  This however I need not remark to you, who know so well from your own observations that the whole of the country I am now speaking of has every character of a primary one.  I, only mention it, that it may not be supposed that the rock in question was some fragment of a secondary stratum that remained, after the rest was washed away, superincumbent on the primary.

“After I had seen this rock, I recollected that you had told me of something of the same kind that you saw in a quarry at Low-wood Inn; and it may be that both belonged to the same stratum or body of strata; for the direction of the strata, as nearly as I could observe, was from S.W. to N.E.; and this also is nearly the bearing of Low-wood from the place where we now were.  I send you a specimen, which you can compare with those you brought from the lime quarry at Low-wood.”

I have examined this specimen, and find it to be the common schistus of that country, only containing many bivalve shells and fragments of entrochi and madrapore bodies, and mixed with pyrites.

I have already observed that one single example of a shell, or of its print, in a schistus, or in a stone stratified among those vertical or erected masses, suffices to prove the origin of those bodies to have been, what I had maintained them to be, water formed strata erected from the bottom of the sea, like every other consolidated stratum of the earth.  But now, I think, I may affirm, that there is not, or rarely, any considerable extent of country of that primary kind, in which some mark of this origin will not be found, upon careful examination; and now I will give my reason for this assertion.  I have been examining the south alpine country of Scotland, occasionally, for more than forty years back, and I never could find any mark of an organised body in the schistus of those mountains.  It is true that I know of only one place where limestone is found among the strata; this is upon Tweed-side near the Crook.  This quarry I had carefully examined long ago, but could find no mark of any organised body in it.  I suppose they now are working some other of the vertical strata near those which I had examined; for, in the summer 1792, I received a letter from Sir James Hall, which I shall now transcribe.  It is dated at Moffat, June 2. 1792.

“As I was riding yesterday between Noble-house and Crook, on the road to this place, I fell in with a quarry of alpine limestone; it consists of four or five strata, about three feet thick, one of them single, and the rest contiguous; they all stand between the strata of slate and schist that are at the place nearly vertical.  In the neighbourhood, a slate quarry is worked of a pure blue slate; several of the strata of slate near the limestone are filled with fragments of limestone scattered about like the fragments of schist in the sandstone in the neighbourhood of the junction on our coast.[22]