The most ancient beds in the county yet known belong, as unequivocally shown by their fossils, to but the middle formation of the system. They have been quarried for many years in the parish of Carmylie; and the quarries, as may be supposed, are very extensive, stretching along a moory hill-side for considerably more than a mile, and furnishing employment to from sixty to a hundred workmen. The eye is first caught, in approaching them, as we surmount a long, flat ridge, which shuts them out from the view of the distant sea, by what seems a line of miniature windmills, the sails flaring with red lead, and revolving with the lightest breeze at more than double the rate of the sails of ordinary mills. These are employed--a lesson probably borrowed from the Dutch--in draining the quarries, and throw up a very considerable body of water. The line of the excavations resembles a huge drain, with nearly perpendicular sides--a consequence of the regular and well-determined character of the joints with which the strata are bisected. The stone itself is a gray, close-grained fissile sandstone, of unequal hardness, and so very tough and coherent--qualities which it seems to owe in part to the vast abundance of mica which it contains--that it is quite possible to strike a small hammer through some of the larger flags, without shattering the edges of the perforation. Hence its value for various purposes which common sandstone is too brittle and incoherent to serve. It is extensively used in the neighborhood as a roofing slate; it is employed, too, in the making of water cisterns, grooved and jointed as if wrought out of wood, and for the tops of lobby and billiard tables. I have even seen snuff-boxes fashioned out of it, as a sort of mechanical feat by the workmen,--a purpose, however, which it seems to serve only indifferently well,--and single slabs of it cut into tolerably neat window frames for cottages. It is most extensively used, however, merely as a paving-stone for lobbies and lower floors, and the footways of streets. When first deposited, and when the creatures whose organic remains it still preserves careered over its numerous platforms, it seems to have existed as a fine, muddy sand, formed apparently of disintegrated grauwacke rocks, analogous in their mineral character to the similarly colored grauwacke of the Lammermuirs, or of primary slates ground down by attrition into mud, and mixed up with the pulverized fragments of schistose gneiss and mica schist.