348 ON THE RED SANDSTONE, MARBLE, 
them is red, in a proportion which no longer obtains among 
the primary rocks of the country. I detected in this sand- 
stone, in the island of Run, thin beds of a gray stratified clay, 
resembling the clay of the ichthyolite beds of Ross and Cro- 
marty ; but, though they inclose occasional nodules, I failed to 
discover in them aught organic. ‘The Old Red Sandstone of 
the west coast, like its probable analogue the Great Conglom- 
erate of the east, is, so far as we yet know, an unfossiliferous 
deposit. I may here mention, that I found at Gairloch in 
Ross-shire, nearly thirty years ago, a variety of this sandstone 
of a finer and closer grain than ordinary, which yielded freely 
to the chisel, and made, — what is by no means common in the 
formation, 
an excellent hewing stone. M’Culloch had not 
yet published his geological map of Scotland; and the limits 
of the various rock-systems in the more inaccessible parts of 
the country were scarce at all known, when I was despatched, 
in advance of a party of workmen engaged to erect a dwelling- 
house on the shores of Gairloch, to find some suitable quarry 
for the rubble-work,—a sort of commission which it was 
thought, though I was but a mere lad at the time, my habit at 
looking at rocks might qualify me to execute. I was struck, 
on my arrival, by the flatness of the promontory which forms 
the northern barrier of the loch, and the general softness of its 
outline, compared with that of the rugged gneiss region around; 
and, immediately setting out to ascertain what sort of a rock 
entered into its composition, I found, somewhat to my surprise, 
that it consisted entirely of red sandstone. But, though I pro- 
cured in abundance ashlar and corner-stones for our purposed 
building, my discovery did not stand my master, the contractor, 
so much in stead as it might; as, in despair of finding sand- 
stone in Gairloch, he had previously freighted a vessel with 
stones for the hewn work from the quarries of Burghead in 
the Moray Frith. As I have already incidentally remarked, 
