which he found them, from a minute and interesting description, for which I am indebted to his pen. Leaving behind us the town at the bottom of its deep bay, we set out to explore a bluff-headed parallelogramical promontory, bounded by Thurso Bay on the one hand, and Murkle Bay on the other, and which presents to the open sea, in the space that stretches between, an undulating line of iron-bound coast, exposed to the roll of the northern ocean. We pass two stations in which the hard Caithness flagstones so well known in commerce are jointed by saws wrought by machinery. As is common in the Old Red Sandstone, in which scarce any stratum solid enough to be of value to the workmen, whether for building or paving, contains good specimens, we find but little to detain us in the dark coherent beds from which the flags are quarried. Here and there a few glittering scales occur; here and there a few coprolitic patches; here and there the faint impression of a fucoid; but no organism sufficiently entire to be transferred to the bag. As we proceed outwards, however, and the fitful breeze comes laden with the keen freshness of the open sea, we find among the hard dark strata in the immediate neighborhood of Thurso Castle, a paler-colored bed of fine-grained semi-calcareous stone, charged with remains in a state of coherency and keeping better fitted to repay the labor of the specimen-collector. The inclosing matrix is comparatively soft: when employed in the neighboring fences as a building stone, we see it resolved by the skyey influences into well-nigh its original mud; whereas the organisms which it contains are composed of a hard, scarce destructible substance,--bone steeped in bitumen; and the enamel on their outer surfaces is still as glossy and bright as the japan on a _papier-mache_ tray fresh from the hands of the workman. Their deep black, too, contrasts strongly with the pale hue of the stone. They consist chiefly of scales, spines, dermal plates, snouts, skull-caps, and vegetable impressions. A little farther on, in a thick bed interposed between two faults, the same kind of remains occur in the same abundance, largely mingled with scales and teeth of Holoptychius, tuberculated plates, and coprolitic blotches; and further on still, in a rubbly flagstone, near where a little stream comes trotting merrily from the uplands to the sea, there occur skull-plates,--at least one of which has been disinterred entire,--large and massy as the helmets of ancient warriors. We have now reached the outer point of the promontory, where the seaward wave, as it comes rolling unbroken from the Pole, crosses, in nearing the shore, the eastward sweep of the great Gulf-stream, and then casts itself headlong on the rocks. The view has been extending with almost every step we have taken, and it has now expanded into a wide and noble prospect of ocean and bay, island and main, bold surf-skirted headlands, and green retiring hollows.