THE OLD RED SANDSTONE. 179 
of Scotland as strongly saliferous as any of the newer sand- 
stones, of well nigh as bright a brick-red tint, of as friable and 
mouldering a texture, and variegated as thickly with its specks 
and streaks of green and buff-color. But in all these instances 
there are strongly characterized groups of fossils, which, like 
the landmarks of the navigator, or the findings of his quad- 
rant, establish the true place of the formations to which they 
belong. Like the patches of leather, of scarlet, and of blue, 
which mark the line attached to the deep-sea lead, they show 
the various depths at which we arrive. The Earls of Suth- 
erland set themselves to establish a coal-work among the 
chambered univalves of the Oolite, and a vast abundance of 
its peculiar bivalves. The coal-borers who perforated the 
Lias near Cromarty passed every day to and from their work 
over one of the richest deposits of animal remains in the 
kingdom —a deposit full of the most characteristic fossils ; 
and drove their auger through a thousand belemnites and 
ammonites of the upper and inferior Lias, and through gryph- 
ites and ichthyodorulites innumerable. The sandstones of 
Strathearn and the Carse of Gowrie yield their plates and 
scales of the Holoptychius, the most abundant fossil of the 
Upper Old Red; and the shale of the little dell in which the 
first Earl of Cromarty set his miners to work. contains, as I 
have said, plates of the Coccosteus and scales of the Osteole- 
pis — fossils found only in the Lower Old Red. Nature, in 
all these localities, furnished the index, but men lacked the 
skill necessary to decipher it.* I may mention that, inde- 
* There occurs in Mr. Murchison’s Silurian System a singularly 
amusing account of one of the most unfortunate of all coal-boring 
enterprises; the unlucky projector, a Welsh farmer, having set him- 
self to dig for coal in the lowest member of the system, at least six 
