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admits the commencement of other vegetation, which in creases as length of time makes a growing humus upon it.*
Gneiss is also a barren rock;t but the feldspar in gneiss is often decomposed, and passes into clay ;then some kind of plants begin to appear upon it. $
Mica slate is also infertile in its natural state, but by disintegrating more easily than either gneiss or granite, becomes, as it decomposes, more susceptible of vegetation. Il
It is with the rocks and strata which have been imposed upon the primordial, that our present vegetation decidedly begins. “CLAY SLATE is more favourable to vegetation than any of the three preceding rocks. It is observed that the quantity of vegetation increases from granite to clay slate.” Hence in Cornwall and Devon, wherever that kind -“Hermitage was first grown among granitic rocks and stones broken smaller by art, and little or no dressing was used."
* Thus the granite near Plymouth, which has been subjected to the action of weather, displays a comparative fertility in grass. “But it is said by gentlemen possessing estates on the granite, and my observation agrees with it, that trees, after reaching a certain height, rise no farther; spreading and twisting their branches without proportionate increase of trunk In Westmans Wood, a plot of oaks, supposed to be a thousand years standing, the largest less than a man's waist, and within 20 feet high, is an extreme instance." -Trans. Plym. Instit.
† Mr. Flint says of New York: “Its island is composed chiefly of gneiss. Whenever the gneiss shows itself on the surface it is barren and desolate. Scarcely can a cedar or a sumach find sustenance for its roots in the crevices of the rock."--Trav. in Am. 42. In his Journey over the Northern Regions of America, Dr. Richardson remarks: “ Gneiss was the most extensively distributed on our track, and always attended with a very scanty vegetation."-P. 535. “The gneiss reappeared, presenting the genuine barren ground, hills, and precipices, together with their vegetable associates ; cenomyce; rangiferina; cetraria nivalis; cornicularia ochrileuca; doufourea arctica, arbutus alpina, rhododendron lapponicum; empetrum nigrum; plants which seem to characterize the barren grounds."--Frankl. Journ. p. 534. "The soil is favourable to these and to some congenerous lichens : but very inimi. cal to every other species of vegetation.”-Ib. 520. I Kirwan's Geol, v. i. p. 347.
“In many other countries even the granitic gneiss decomposes as readily as some granites, forming a deep and rich soil; as in Guernsey, and also in Aberdeenshire, remarkable for the destruction of all its rocks, and for the great depth of its untransported alluvia."-McCull. v. ii. p. 154.
“This rock often presents considerable fissures, and mouldering more readily than gneiss, is favourable to vegetation : the lower clefts and precipices are often covered with trees." -- Ib. p. 157.
Jameson, Miner. v. iii. p. 124. “Mountains of slate are covered with verdure on their declivities, as they contain less silex, and a more equal admixture of the earth favourable to vegetation."--Bakew, Goal.
of slate which they call killas lies upon the granite, a flourishing vegetation is seen.*
But limestone is as important to prolific vegetation as clay ; it was therefore necessary to provide this in due abundance, and to place it so near the surface, as to be disintegrated enough to mingle with the other earths, and to be useable by man. This has been admirably accomplished in the last disposition of our surface. It is in every country in a sufficient quantity for its fertilizing benefit,t and due provision has also been made, that the primordial rocks should everywhere be so broken and comminuted, as to furnish every region with a competent proportion of sandy soil ; a due mixture of which is highly serviceable to the growth
124. “As clay slate generally decomposes readily into clay, of different degrees of tenacity, it presents a great variety of soil, favourable both to agriculture and the growth of wood."-McCull, v. ii. p. 192.
*“At Buckland, on the Dart, where the killas runs in a trough between two granite mountains, the vivid green of the turf, and the rich wood running up the acclivities, contrast strikingly with the pale herbage and bald crowns of its over-topping neighbours. At Yalland estate some fine trees appeared in the midst of the granite. On approaching them, they were found to be growing in a patch of the killas; not a tree spreading out to either side."--Prideaux, Trans. Plymouth Instit.
* Mr. Flint mentions this effect in several of the new states of North America. “The soil in East Tennessee has uncommon proportions of dissolved lime, and nitrate of lime, mixed with it, which give it a great share of fertility.”-Flint, Am. Geol. p. 335. In Kentucky, “ Under its great valley, at a depth of from three to ten feet, is a substratum of limestone. So much dissolved lime is mixed with the soil, as to impart to it a warm and forcing quality, which, when the earth is sufficiently moist, imparts an inexpressible freshness and vigour to the vegetation."-Ib. 347. The Mississippi Valley. “From its character of recent formation ; from the prevalence of limestone everywhere; from the decomposition it has undergone and is constantly undergoing; and from the considerable proportion of decomposed limestone in the soil, probably results its uncommon fertility." --Ib. p. 17. or the Missouri State he mentions: “ The warmth and looseness of the soil, and the large proportion of dissolved limestone in it; and even the dryness of the atmosphere, render it an admirable country for wheat. Twentyfive bushels an acre are an average crop, though it sometimes runs as high as thirty."--1b. 288.
The animal-made lime rocks are as beneficial in the Arkansas territory. “In the whole depth vast quantities of seashells appear. In a state of pulverization, they are mixed with the soil, and communicate a very great fertility to it."--Flint, N. Am. p. 280.
Captain Franklin observed the same effect near the Arctic Regions at Cumberland House. "The land around it is low, but the soil, from having a considerable mixture of limestone, is good, and capable of producing abundance of corn, and vegetables of every description."Journ. 55.
and abundance of our botanical riches ;* indeed sand enters largely into the composition of all grasses and straws. It is very favourable to the growth of the cotton plant. I
The plan having been settled in the divine economy of earthly things, that the animal kingdom should subsist principally on grass, it became an indispensable point that this should be everywhere provided for them where they were meant to be. Most kindly has this been managed, and by the sagacious contrivance, that grasses should not be one species of plant suited to one kind of soil only ; but that they should be multiplied into many distinct sorts, and that each of the decomposed rocks should thus have grasses adapted to it, so as to vegetate on the peculiar soil it makes ; hence “a grass can be found adapted to the soil, let it be ever so sterile or ever so fruitful.”'s The quantity of grass
* The Missouri State, in North America, is an instance of this. “The land here contains a greater proportion of SAND, is more loamy and friable, and the soil not so stiff. The tracts where we find the clayey soils of Kentucky and Ohio are small. The bottoms of the Missouri are generally loamy, with a large proportion of sand. But even where the proportion of sand seems in excess, the soil is of the richest character; and at first more productive than that of the Upper Mississippi."--Flint, Geol. 287.
In England, "the clay soils are generally covered with timber; the sand and limestone surface is occupied as arable land; and the alluvium as meadow."--Lance, Gold. Farm. 52. “Land, the principal part of which was sand, has from the peculiar union of the grasses, and a plentiful supply of water, fattened bullocks of 160 stone and wintered 400 sheep per acre."--Ib. p. 41.
† “ The whole matter of barley and its straw contains more sandy particles than any other grain cultivated by the British farmer. Sir H. Davy found that two canes rubbed together produced a light; but not so when the epidermis was taken off. This he found had the property of silex; so had straws and grasses."--Ib. p. 17.
I “Cotton succeeds in light sandy soils, moderately moist. Volcanic soils are found best to agree with the cotton plant. The soil next in rauk, favourable to its growth, is a fine sand, whose particles are held together by a small portion of clay or calcareous earth ; particularly if mixed with decomposed vegetable matter."--Porter's Tropical Agric.
Lance, p. 39. M. Sinclair says, " There are upward of 130 distinct species of grasses, besides varieties, native to Great Britain. There is no variety of soil, intermediate between the high rock or the blowing Band, down to the marsh, the bog, even water itself, but is provided, by the bountiful hand of nature, with grasses peculiarly adapted to grow and remain permanent on each particular soil and site.
“ The sorts combined vary according to the nature of the soil. If BAND is the principal ingredient, then we find rescue grass, smooth fescue, fine-bent, creeping soft, tuft-leaved bent, crested dog's tail, smooth stalked meadow, meadow soft grass.
raws and then off. Thiser produced
upon a small space, and its productiveness, evince the exuberant principle on which the bountiful Creator has formed and provided this order of vegetable nature.*
The basaltic and trap rocks have been so formed, both as to their component substance and mode of cohesion, that they shall be decomposable, and in their decompounded state, shall also administer soil that will suit and promote vegetation of some kind or other. The lava of volcanoes also in time decomposes and becomes an earthy matter, in which herbs and trees find a soil that sustains them.I
The provisions, and adaptations, and varieties of kind of inventions for the production, on every sort of soil, and
“CALCAREOUS soils abound with the rough-headed cocksfoot grass, meadow fescue, hard rescue, perennial rye, upright perennial, brome, yellow oat, sheep's fescue.
"Argillaceous soils encourage meadow or timothy grass ; Pacey's improved rye grass, meadow foxtail, rib grass or lamb's tongue florin, creeping bent, tall oat grass, and others."--Sinclair on Lance, p. 40.
**A soil mixed of the three principal earths has been found to have on a foot square 22 distinct species and 1100 distinct roots of individual plants, and this pasture has fatted one large ox and three sheep per acre in the season "--Lance, p. 41. But “to maintain proper herbage in a field, care should be taken that the hedges are kept free from weeds, or they will soon occupy the vacant spaces between the roots of the grasses."-"Clover is found to flourish most where there is a sulphate of lime in the mixture."--Ib. This last remark shows the use of gypsum among the strata, as this is a sulphate of lime.
t" Basalt is very subject to decomposition ; particularly those varieties which incline to wacke and amygdaloid. The earth which is formed from the decomposition of basalt has a greasy feel. The great fruitfulness of basalt countries is owing to the basaltic earth."--Jameson, Min.' v. iii. p. 188. Capt. Owen observed near Cape St. Sebastian, Madagascar: « The immediate vicinity of this bay was formed of huge misshapen columus of basalt, covered with forest trees and long grass, where herds of wild cattle were seen grazing in fearless security." Owen, Voy, v. ii. p. 185.
I Dr. Clarke mentions in his Travels, that in Galilee, “in all the descent towards Tiberias, the soil is black and seems to have resulted
from the decomposition of rocks which have a volcanic appearance." - In the Sandwich Islands Mr. Ellis found the surface in some parts
entirely covered with a rich mould formed by decayed vegetable matter and decomposed lava.--Tour in Hawaii, p. 46. Where the lava was indurated it was barren, " yet wherever the volcanic matters have undergone any degree of decomposition, the sides of the mountains, as well as the ravines by which they are intersected, are covered with shrubs and trees."--Ib. p. 8. So he found vegetation on the extinct craters. “Some of these craters appeared to have reposed for ages, as trees of considerable size were growing on their sides, and many of them were covered with earth and clothed with verdure."
species of rock, of those trees of our fields and forests which supply us with such beautiful scenery, and essential conveniences, and which, at the same time, are the comfortable 'homes and support of the bird and insect classes, and of so many quadrupeds, have not been less numerous or beneficent. Such care has been taken in the adjustment of soil to tree, and tree to soil, that every kind of rock that decomposes so much as to afford any penetrable matter for roots to extend in, sustains and furnishes some useful or pleasing trunks and foliage.* So fitly and adaptedly has the vegetable structure been made for the earthy masses of our planet, that “ plants and trees, the roots of which are fibrous and hard, and capable of penetrating deep into the earth, will vegetate to advantage in almost all common soils that are moderately dry, and which do not contain a very great excess of vegetable matter."'t
We cannot doubt, as we study the present nature of our surface, that it has been most carefully adapted to develop and nourish its intended vegetative offspring. I
* Thus though the country round Fort Providence, on the Great Slave Lake in North America, consists almost entirely of coarse-grained granite, “the surface is generally naked, yet in the valleys between its hills a few spruce, aspen, and birch-trees grow, together with a variety of shrubs and berry-bearing plants."-Frankl. Journ. p. 209. “Three fourths of all vines are grown on hills; and wines of the first character are made from vines that flourish among stones and pieces of rock. No wine of tolerable quality is grown on rich and highly-dressed land."--C. Redding on Wines. “Between Rocky and Carp Lake the granite contains many beds of MICA SLATÆ, passing into clay slate ; yet the country is tolerably well wooded. White spruce occupies the rocky situations, pinus banksiana the sandy spots, aspen the low moist plains.”-Franklin, p. 520. “The soil of the country about Hayes river nourishes a pretty thick forest, consisting chiefly of spruces, larches, and poplars, but the trees are small, as the subsoil is perpetually frozen."-Ib. 499. On a farm in Llanvan parish in Wales two very lofty lime-trees or linden are growing on limestone." The elm grows most luxuriantly in the red sandstone soil, without planting and without care. The oak grows best in the stiff blue clay. The beech is best on the limestone brash.”-Lance, Gold. F. p. 15.
+ Sir H. Davy's Analysis of Soils, p. 15.
I “If there was ever a time when the materials composing this globe were collected into solid masses, such a condition must have excluded organic life. The formation of the soil has been apparently a work of time, and the result of the gradual attrition of the solid materials composing the crust of the globe. Hence the formation of soil has probably been always progressive, and is still going on. Besides this gradual attrition, the harder materials of our globe seem to have suffered much disintegration during the periodic convulsions formerly mentioned. By