and produces its successor.* Aqueous plants would in like manner arise, as their seeds were wafted to watery places. And in this way vegetation may have originally spread from the district where it was flourishing, to those which it had not before reached. This progressive diffusion would journey far beyond the disseminating process of animals or man, and would so far precede them, that long before they could extend their dispersing colonies around, the earth would be everywhere abundantly clothed with all that either could require. We infer that this was the primitive mode in which vegetation was spread over the earth, because we know that the largest portion of the herbs and trees which any nation now possesses has been thus successively introduced. We can trace the chronology, and date the origin, of no small part of our own insular vegetation; as we can of several of our fish and animals. From what we know to have thus taken place in the later ages of the world, we reason up to what most probably occurred in its primordial times. In this diffusing process, the most diffusible would be the first, and the most universally diffused; and this truth explains the fact, why the cryptogamiæ are in many places, both antediluvian as well as postdiluvian, found to have been the original vege tation, As far as we can reason from existing phenomena, it would appear that vegetables do not grow upon any thing but vegetable matter, except the simplest cryptogamias, which begin the curious process on bare rocks or mineral earth, and, by their decay, provide the first nutritive mould on which other seeds germinate. All plants have the property of adding to their organization carbonaceous matter. Whether they make it by some unknown process of their living principle, or separate it from the atmosphere, it is *In M. de Brebisson's Memoir on the Vegetation of Lower Normandy, it is remarked, that the mineralogical nature of the soil exercises an influence on the geographical distribution of plants. The cryptogamias particularly appear to prefer individual species of rocks. In the secondary formations he observed a number of plants that were never found in the more ancient earths. It is generally believed that the number of the algæ is less considerable in the secondary rocks than in the anterior ones. The thalassiophytes floridées seem to have preferred the calcarious ones; while the fucacées abound on the submerged granits of the latent ones.-Feruss, Bull. Uniy. 1829, p. 54 certain that their substance while they live, and their remains when they die, largely contain it. Thus every decayed vegetable leaves a carbonaceous mould for the nutrition and growth of new ones.* It is the appointed nature of lichens to evolve their vegetation without a previous vegetable soil; and thus to commence the formation and deposite of the particles of carbon, which are the food that all roots seek and imbibe ;† but all plants, excepting those which can thus grow on the bare mineral rock, require a provided bed of vegetable matter for their seeds to grow in, which is by this process gradually obtained. The whole surface of the earth, that is not a sandy desert or a denuded rock of stone, has by these means become covered with layers of vegetable matter, in the successive additions of nearly 6000 years. Every spring a new growth of plants, in their various classes, arises around us, and decays every autumn. Their annual remains then falling and decomposing, mingle with the earth they sprouted from, and thereby increase its power of nourishing new ones. The warmer the climate, the less need appears for the simpler ones to precede, if there be aerial carbon or matter enough to give them the nutrition they require. But in all regions, the mosses, grasses, herbs, and leaves, and decomposing bark and wood, have been every season laying their decompounded matter in successive strata on the general soil, till earth has become strewed with the vegetable ruins and riches of almost sixty centuries. In proportion as this accumulation has increased, • Saussure conceived that his experiments proved that plants, during their growth, acquire an additional quantity of carbon.-Rech. p. 50-53. "The conjoined evidence of the experiments of Braconnot, Shrader, and Emhof seems to prove very clearly that we cannot account for the introduction of the constituents of vegetables from the soil or water with which they are in contact."-Bostock's Phys. vol. ii. p. 388. • Pulverulent lichens are the first plants that clothe the bare rocks of newly-formed islands in the midst of the ocean. Foliaceous lichens follow these, and then mosses and hepatice. The same species seem to be found in many different parts of the world. Thus the lichens of North America differ little from those of Europe.-Linds. N. S. 333. Two of the hepatice were found in Melville Island, in the north polar Ocean 1 Humboldt remarks,-"It is not in general by mosses and lichens that vegetation begins in the countries near the tropics. In the Canary Islands, as well as in Guinea and in the rocky coasts of Peru, the first vegetables that prepare the mould for others are the succulent plants."-Humboldt's Geog. des Plantes. the soil of every country has become more fertile; and this fact strengthens the supposition, that the vegetation of every country has progressively advanced in the multiplicity of its species, according as its organic mould became thus every year more and more enlarged and fitted to receive and nurture the more important plants. Only plants with short roots can grow on a scanty soil. Its quantity of vegetable mould must be augmented, before trees with deeper roots can largely grow, or permanently abide. They will germinate on almost any portion of such matter, but soon perish if the earth be not sufficient for their increasing development. Hence it appears most probable that the first miraculous production of vegetation was limited to such a locality as would admit of all its species to appear; and that from this commencing nursery, it was gradually disseminated from region to region, according to the laws and qualities of each individual species. The simpler cryptogamias, the lichens and mosses, would diffuse themselves on the barren rocks and mineral surface, to begin the first layers of carbonaceous matter. The simple fern tribes would find in this sufficient nourishment for their evolution. Their remains would enable the floating seeds of the grasses to find a congenial bed for their rapid growth; and their decay would so enrich the organic mould, that deeper-rooted plants would find a proper bed for their nutrition, and by their multiplication and decay enable the larger trees to grow; and as their falling leaves augmented the accumulation of the nutritive matter, forests of every magnitude would flourish upon it.* * Dr. Johnston mentions of the ash, that its winged seeds are so readily borne about by the winds, that no tree is so often met with in ruins and upon ancient walls. It insinuates its roots far into the crevices of these old buildings. In like manner it fastens upon loose slaty rocks, and adorns them with its verdure.-Flora of Berwick..... The plane has also wings; likewise the pine. though shorter.. "Those of the typha, dandelion, and most of the pappous kind have long and numerous feathers, by which they are wafted every way."-Grew. Anat. p. 199. Theophrastus noticed the distant conveyance of seeds by birds.-Plant. 1. 2. c. 24.-And Pliny observes that the misseltoe was planted by them on trees, conceiving that its growing powers were increased by having been in the animal body.-L. 16, c. 44... Tavernier remarked that birds from other islands swallowed the ripe nutmeg, but threw it up before digested, when it took root and produced a tree that would thrive better from them than if planted by huinan hauds. Thevenot mentions the same fact.....The Dutch were so aware of the services of these |