The first plant that burst from the soil had thus every element provided which its nature and habits required—the light, to which it turns and ever yearns after—the air, in which to perform its respiratory functions—the water, from which to secrete the juices of circulation—and a dry land, out of which to elaborate materials for its structure. This is a Wisdom which is above all philosophy, instructing in the elements and principles of things, long before botanical arrangements were dreamed of, or “bushy dell” there was, where “hoary-headed frosts Fall in the fresh lap of the crimson rose.” The silurian group of rocks is very widely extended, as in Britain, France, Russia, the north-west of Asia; in South Africa, North and South America, the Falkland Islands, and Australia. The most ancient physical features of the Old World can almost be recalled, as we thus trace the outline of the deposit, marking out, by its geographical distribution, the primary islands and mountain peaks of the aboriginal land. How changed the very face of things—continuity between states and kingdoms where seas now roll—and all the great continents occupying the sites over which the waters held unbounded sway! [Illustration: Trilobites of the Silurian System.] CHAPTER IV. THE DEVONIAN SYSTEM, OR OLD RED SANDSTONE. A geologist requires not, like the tourist, to be told of the various conflicting roads that run among the mountains, in what precise course he is to wend his way. He will follow his own pathways, roads of nature’s forming, guided by the strike and lie of the rocks rather than by the beaten tracks of every-day life. But come whither he will—through Glentilt, Glenericht, Glenbeg, and the Spittal, Glenisla, and Clova,—or along the Dee, the heights of Glentanner, and penetrating to the sources of the Esks—sure we are, when he reaches by any of those passes the frontiers of the Grampians, he will pause and gaze wistfully, thoughtfully, admiringly, ere he descends, upon the magnificent prospect that stretches before him, unrivaled by any on the terraqueous globe. The GRAN-PEN, _celticé_, the shelvy or precipitous summit, Romanized into Grampius, has its own inner charms, peaceful rock-girt valleys where princes dwell, and happy as Rasselas ever trod.—And escaped from these, what an outer world beneath, fertile, abundant, replete with everything that can charm the eye or interest the student. Looming in the far distance, the Lammermuirs, of silurian origin, can just be descried as a dark-blue line on the verge of the horizon; the Ochils and Lomonds, of carboniferous age, repose like islets on the pendant sky; while, in the foreground of the picture, there is the most charming variety of woodland, meadow, farmstead, town, and mansion, all as I now gaze upon them in their autumn coloring, invested with a Claud-like mellowness that speaks with a moral yet romantic sympathy to the heart. The round tower