631. While the fundamental earths were precipitated, the calcareous earth was repelled and retained, on account of its homogeneity, in water, because the acid half continued longer fluid than the basic. The water was thus after its separation from these substances a true limewater.
632. Through this separation, however, the great antagonism in the water ceased; and subordinate antagonisms now made their appearance, which were kept united by the former. The calcareous earth is now occupied no more as one pole, but is the whole water itself, upon which, as it is less deep, the light acts anew and with greater force.
633. The dispersions of earths began just at this period to multiply themselves, from the only fettering agent, namely gravity, having betaken itself to rest; every earthy now emerges from its connexions, the factors falling wholly asunder into alkalies and acids, which combine in a multifarious manner.
634. These dispersions associated with the torrents of water that were now everywhere present prevented crystallization from taking place upon a large scale; they moreover mingled with the mechanically water-borne and crumbling débris of the earlier species of rocks; their laminations therefore resemble rather a mechanical deposit from water. They are the Stratified rocks.
635. As the first period must include the calcareous earth, so also in the period of strata or in the dualized period this earth is not without a slight antagonism of the fundamental earths; and this it is which for the first time becomes distinct, but always with a preponderance of the calcareous over the fundamental earths, while in the primary periods this relative proportion of the two was the reverse.
636. The primary period repeats itself again in the second, and thus strata consisting of the fundamental earths originate, as we have seen exemplified in the primary and transition formations of limestone. The precipitation of strata is divided also into four formations, into silicious, argillaceous, talcose and calcareous strata, close to which range also the strata of ores, Inflammables and salts.
637. In other respects the chemical deposits of this period are so blended with the mechanical, that their mode of origin seems for the most part to have happened in both ways.
638. The silicious formation returning in the stratified periods is chiefly under the condition of sandstone. Apart from that, which has originated through the detritus of the older kinds of rocks, it may be assumed, that the prevailing lime still held some silicious earth in a state of moisture within itself, and that this during its separation was precipitated as a fine alcohol, namely, as sand. If, however, sand fell, so also must a proportionate quantity of lime fall, by combining itself with an acid. Sand and lime therefore usually accompany each other. If the two be regarded also as only floated freely and suspended in water, still the chemical antagonism manifests itself between them as if they were in a mortar, and they have been precipitated in layers alternating with each other. The sandstone is as a rule therefore imbedded in the lime; it is a mortar containing but little lime. The mechanical silicious deposits are exemplified in the Nagelfluh, old red sandstone, Grauwacke, sandstone and drift-sand.
639. The stratified clay appears to have been deposited as clay-stone; it passes over into slate and potters' clay. The talcose strata pass by serpentine and potters' stone into steatite and meerschaum.
STRATIFIED LIMESTONE.