65. The Neptunists will no doubt allege, with BERGMAN, that, in the drying of starch, clay, and a few other substances, something analogous to basaltic columns is produced. Here, however, a most important difference is to be remarked, corresponding very exactly to one of the characters which we have all along observed to distinguish the products of aqueous, from those of igneous consolidation. The columns formed by the substances just mentioned, are distant from one another: they are separated by fissures which widen from the bottom to the top, and which arise from the shrinking and drying of the mass. In the basaltic columns, no such openings, nor vacuity of any kind is found; the pillars are in contact, and, though perfectly distinct, are so close, that the sharp edge of a wedge can hardly be introduced between them. This is a great peculiarity in the basaltic structure, and is strongly expressive of this fact, that the mass was all fluid together, and that its parts took their new arrangement, not in consequence of the separation of a fluid from a solid part, by which great shrinking and much empty space might be produced; but in consequence of a cause which, like refrigeration, acted equally on all the parts of the mass, and preserved their absolute contact after their fluidity had ceased. 66. A mark of fusion, or at least of the operation of heat, which whinstone possesses in common with many other minerals, is its being penetrated by pyrites, a substance, as has been already remarked, that is of all others most exclusively the production of fire. Another mark of fusion, more distinctive of whin, is, that both in veins and in masses it sometimes includes pieces of sandstone, or of the other contiguous strata, completely insulated, and having the appearance of fragments of rock, floating in a fluid sufficiently dense and ponderous to sustain their weight. Though these fragments have been too refractory to be reduced into fusion themselves, they have not remained entirely unchanged, but are, in general, extremely indurated, in comparison of the rock from which they appear to have been detached. 67. Similar instances of extraordinary induration are observed in the parts of the strata in contact with whinstone, whether they form the sides of the veins, or the floors, and roofs of the masses into which the whinstone is distributed. The strata whether sandy or argillaceous, in such situations, are usually extremely hard and consolidated; the former in particular lose their granulated texture, and are sometimes converted into perfect jasper. This interesting remark was first made by Dr Hutton, and the truth of it has been verified by a great number of subsequent observations.