These are instructive facts, yet greatly to be extended, when, we question not, the land will also contribute of its flora to complete our knowledge of the most ancient fossiliferous strata.—But recently, bands of true coal have been discovered completely inclosed in this group of rocks near Oporto, the town of which stands on a ridge of granite, four or five miles wide, with mica-slate and gneiss resting on both sides. To the eastward, these again are overlaid by sedimentary rocks, chiefly clayslate; which, commencing on the coast about thirty miles north of Oporto, run down and cross the Douro, about sixteen miles above that town.—To the south of Vallango, the strata overlie a deposit of anthracite in several beds, some of them from four to six feet thick.—This coal is now worked in several pits, and principally sent to Oporto. Along with it are beds of red sandstone and black carbonaceous slates, with vegetable impressions too indistinct to be determined, but strongly resembling ferns of the coal measures. In the shales above this coal Mr. Sharpe, the discoverer, found many fossils, as orthides, trilobites, and graptolites, most of them new species, but others well known in the lower silurian rocks of Northern Europe. It would thus appear that the coal deposits of Oporto are included in the silurian formation, and are far below the usual level of the coal. We cannot overvalue the theoretic importance of these discoveries, which do not indeed bring to light any exuberant variety of the vegetable tribes, such as the earth afterward threw out of her affluent bosom. But they mark sufficiently the period when plants, according to the geological reading of the history, first make their appearance on these lithological pages: fucoids and algæ are there in abundance, to give the vegetable portion of the narrative, as trilobites and molluscs form unquestionably the predominating features of the animal department. The coal-beds of Oporto—should their position turn out to be truly defined—show the dawning of a terrestrial flora, not sparingly but luxuriantly developed: and thus the silurian period may be regarded throughout as sufficiently characterized by well-marked types of vegetation, more doubtful in the higher forms, but determinate in the acotyledonous and cryptogamic tribes which prevail indifferently from the lower to the upper beds of the system. Nor do we require to overstrain the statement, by questioning nature or revelation as to the species, genera, orders, and classes of vegetables referred to in their respective pages. They are coincident as to the great truth itself, that PLANTS did exist in the earliest “days” of the earth’s history. As a science, nothing is taught in the Sacred Record. None of the technicalities of physical inquiry are employed. But a beautiful progression, and elimination of one thing after another, are intimated. The light is separated from the darkness. A firmament is set in the midst of the waters.