I observed, besides, in the quarry, remains of the huge crustacean of Balruddery. The plates of the _Cephalaspis_ retain the color of the original bone; the plates of the crustacean, on the contrary, are of a deep red tint, which contrasts strongly with the cold gray of the stone. They remind one, both in shape and hue, of pieces of ancient iron armor, fretted into semi-elliptical scales, and red with rust. I saw with one of the workmen what seemed to have been the continuous tail-flap of an individual of very considerable size. It seemed curiously puckered where it had joined to the body, much in the manner that a gown or Highlander's kilt is puckered where it joins to the waistband; and the outline of the whole plate was marked by what I may venture to term architectural elegance. The mathematician could have described it with his ruler and compasses. The superintendent pointed out to me another plate in a slab dressed for a piece of common pavement. It was a regularly formed parallelogram, and had obviously composed one of the jointed plates which had covered the creature's body. I could not so easily assign its place to yet a third plate in the possession of the Rev. Mr. Wilson, of Carmylie. It is colored, like the others, and like them, too, fretted into minute scales, but the form is exactly that of a heart--not such a heart as the anatomist would draw, but such a heart, rather, as we see at times on valentines of the humbler order, or on the ace of hearts in a pack of cards. Possibly enough it may have been the breastplate of this antique crustacean of the Cornstones. The spawn of our common blue lobster is composed of spherical black grains, of nearly the size of mustard-seed. It struck me as not very improbable that the reticulated markings of the flagstones of Carmylie may have been produced by the minute eggs of this fossil crustacean, covered up by some hastily deposited layer of mingled mud and sand, and forced into the polygonal form by pressing against each other, and by the weight from above. The gray fissile bed in which these organisms occur was perforated to its base on two several occasions, and in different parts of the quarries--in one instance, merely to ascertain its depth; in the other, in the course of excavating a tunnel. In the one case it was found to rest on a bed of trap, which seemed to have insinuated itself among the strata with as little disturbance, and which lay nearly as conformably to them as the greenstone bed of Salisbury Crags does to the alternating sandstones and clays which both underlie and overtop it. In the other instance the excavators arrived at a red, aluminous sandstone, veined by a purplish-colored oxide of iron. The upper strata of the quarry are overlaid by a thick bed of grayish-red conglomerate.