base of the superstructure planted on the existing scene stretches across the entire scale on life, animal and vegetable; but it contracts as it rises into the past;—man,—the quadrumana,—the quadrupedal man,—the bird and the reptile are each in succession struck from off its breadth, till we at length see it with the vertebrata, represented by only the fish, narrowing as it were to a point; and though the clouds of the upper region may hide its apex, we infer, from the declination of its sides, that it cannot penetrate much farther into the profound.” In our author’s next chapter, the _twelfth_ of the series, he proceeds to examine the “Lamarckian hypothesis of the origin of plants, and its consequences.” In his _thirteenth_ chapter, on “The two Floras, marine and terrestrial,” he has shown that all our experience is opposed to the opinion, that the one has been transmuted into the other. If the marine had been converted into terrestrial vegetation, we ought to have, in the Lake of Stennis, for example, plants of an intermediate character between the algæ of the sea, and the monocotyledons of the lake. But no such transition-plants are found. The algæ, as our author observes, become dwarfish and ill-developed. They cease to exist as the water becomes fresher, “until at length we find, instead of the brown, rootless, flowerless fucoids and confervæ of the ocean, the green, rooted, flowering flags, rushes, and aquatic grasses of the fresh water. Many thousands of years have failed to originate a single intermediate plant.” The same conclusion may be drawn from the character of the vegetation along the extensive shores of Britain and Ireland. No botanist has ever found a single plant in the transition state.