in marshes; because the clouds, arrested in their progress by such elevations, keep the air in a state of perpetual moisture, somewhat resembling that of the fogs in meadows and marshes; in exemplification of this fact, the locality of parnassia palustris immediately suggests itself to our notice.

"The essential character of a growan, or granitic soil, may be stated to be a peculiar unsusceptibility to all external agents, and an inaptitude in its internal composition, to those chemical changes with which fertility seems connected. There is rarely much soluble matter in such soils. These observations, however, apply with different degrees of force to different districts, according to the value of the soil, and to the extent of judicious improvement which it may have undergone. As a rule for the amelioration of a growan soil it may be recommended, as a general principle, to increase the number of its elements, and, consequently, to extend their affinities. The Cornish code of agricultural improvement, and which, indeed, may be applied to most primitive districts, is to be very shortly expressed-MIX, COMBINE, AND MULTIPLY MANURES. - In the treatment of a siliceous soil, in particular, the manures cannot be too complicated; and those of an animal and vegetable nature should be always previously mixed with clay, decomposing slate, or other illaceous matter, with which they may contract an intimate union, and by such means be more securely preserved in the land to which they are applied. Mr. Scobell, of Nancealverne, near the Land's End, communicated to the author a singular practice which the farmers in his neighbourhood pursued with evident advantage, that of actually

dressing their sterile lands with the comminuted fragments of decomposing granite. Strange and problematical as such a practice may appear to the agriculturalist, who has not studied the subject of mineral manures, to the chemist it is a fact of easy and satisfactory explanation; the decomposing granite contains, as before stated, large quantities of felspar, and therefore of alumina, with, perhaps, small quantities of alkali. Upon the same principle the application of decomposing clay-slate proves a valuable manure for siliceous lands, since it contains alumina in great quantities, and is therefore capable of imparting to them that tenacity of which such soils are destitute.

"The intermixture of soils, or of decomposing rocks capable of producing them, where one kind of earth is either redundant or deficient, has been most successfully practised in other counties. Mr. Bakewell, in his Introduction to Geology, observes, that part of Lancashire is situated on the red sand rock, which being principally composed of siliceous earth and the oxide of iron, forms of itself very unproductive land; but that, fortunately, in many situations, it contains detached beds of calcareous marle, by the application of which it is converted into a most fertile soil. Mr. Brende has also remarked, that experience and science have greatly improved the advantages to be derived from the proximity of different soils to each other, and that there can be no better illustration of the utility of an intimate acquaintance with the relation of the different strata, than the amelioration of the Suffolk sands, which, by the proper application of a substratum of a shelly marle, provincially termed crag, have been

changed from a parched and useless heath to arable and productive land.

"A most interesting illustration of the above views seems to be presented in an extraordinary fact lately discovered in the county of Cornwall, respecting the increased fertility which characterises soils that are superincumbent upon the junctions of rocks. The most superficial observer may easily satisfy himself of the truth of this fact: indeed the line of junction between the granite and slate formations may, in many parts, be traced by the eye alone through tracts of cultivation, from the remarkable fertility which attends it. It may be defined a zone of fertility, since both the growan and slaty soils become mutually enriched as they approach each other; numerous are the examples which might be adduced in confirmation of this fact; the following, as being accessible to investigation, are here particularised. The most valuable part of the estate of Trangwainton, the seat of Sir Rose Price, Bart., lies upon a junction of slate and granite; this line may be traced to Madron church, and from thence round the Mount's Bay, in the direction of which we shall invariably find the superincumbent soil distinguished for its superior fruitfulness. It is, perhaps, worth notice, that all the villas around this beautiful bay are placed upon the junction of rocks. Where the hornblende formation intrudes itself, the fertility of the land is still further increased, as may be seen on the valuable estates of Castle Horneck and Trereiffe. The zone of fertility may be also seen well characterised on the line of junction between granite and slate at Penrhyn, and on that extending from Chyoon on the acclivity of Paul Hill, to Mousehole, in the Mount's

Bay; this latter instance attracted the attention of Mr. Worgan, who, in his general view of the agriculture of Cornwall, notices this district as one highly fertile, and as being famous for producing two crops of potatoes in one year. On Saint Michael's Mount, that "precious stone, set in the silver sea," the geologist will also discover a good example of the fertilizing influence which the junction of slate and granite exerts upon the superincumbent soil; the beautiful carpet of herbage covering the south-eastern base of this singular spot is a feature which instantly strikes the attention of the stranger."

NOTE 13. p. 220.

The geological researches of Doctor Buckland, have been long directed by a desire to accumulate facts, to prove that there must have been an universal inundation of the earth; and, in his inaugural lecture, he has presented us with a summary of such facts which, to use his own expression, whether considered collectively or separately, present such a conformity of proofs, tending to establish the universality of a recent inundation of the earth, as no difficulties or objections that have hitherto arisen, are in any way sufficient to overrule. The facts are as follow.

"I. The general shape and position of hills and valleys; the former having their sides and surfaces universally modified by the action of violent waters, and presenting often the same alternation of salient and retiring angles, that mark the course of a common river; and the latter, in those cases which are called valleys of denudation,

being attended with such phenomena, as show them to owe their existence entirely to excavation, under the action of a flood of waters.

II. The almost universal confluence and successive inosculations of minor valleys with each other, and final termination of them all in some main trunk, which conducts their waters to the sea; and the rare interruption of their courses by transverse barriers producing lakes.

III. The occurrence of detached insulated masses of horizontal strata called outliers, at considerable distances from the beds of which they once evidently formed a continuous part, and from which they have been separated at a recent period, by deep and precipitous valleys of denudation.

IV. The immense deposits of gravel that occur occasionally on the summit and slopes of hills, and almost universally in valleys over the whole world; in situations to which no torrents or rivers that are now in action could ever have drifted them.

V. The nature of this gravel, being in part composed of the wreck of the neighbouring hills, and partly of fragments and blocks that have been transported from very distant regions.

VI. The nature and condition of the organic remains peculiar to this gravel; many of them being identical with, and others not distinguishable from, species that now exist, and very few having undergone the smallest process of mineralization. Their condition resembles that of common grave bones, being in so recent a state, and having undergone so little decay, that if the records of history, and the circumstances that attend them, did not absolutely forbid such a supposition, we should be in