The animal remains, though less numerous, are more interesting. They are identical with those of the Den of Balruddery. I saw, in the possession of the superintendent of the quarries, a well-preserved head of the _Cephalaspis Lyellii_. The crescent-shaped horns were wanting, and the outline a little obscure; but the eyes were better marked than in almost any other specimen I have yet seen, and the circular star-like tubercles which roughen the large occipital buckler, to which the creature owes its name, were tolerably well defined. I was shown the head of another individual of the same species in the centre of a large slab, and nothing could be more entire than the outline. The osseous plate still retained the original brownish-white hue of the bone, and its radiated porous texture; and the sharp crescent-shaped horns were as sharply defined as during the lifetime of the strangely organized creature which they had defended. In both specimens the thin angular body was wanting. Like almost all the other fish of the Old Red Sandstone, the bony skeleton of the _Cephalaspis_ was external--as much so as the shell of the crab or lobster: it presented at all points an armor of bone, as complete as if it had been carved by the ivory-turner out of a solid block; while the internal skeleton, which in every instance has disappeared, seems to have been composed of cartilage. I have compared its general appearance to a saddler's cutting-knife;--I should, perhaps, have said a saddler's cutting-knife divested of the wooden handle--the broad, bony head representing the blade, and the thin angular body the iron stem usually fixed in the wood. No existence of the present creation at all resembles the _Cephalaspis_. Were we introduced to the living creatures which now inhabit the oceans and rivers of Mars and Venus, we could find nothing among them more strange in appearance, or more unlike our living acquaintances of the friths and streams, than the _Cephalaspides_ of Carmylie.