Mr. Mackintosh replied in a brief paper, in which he refused to accept my correction of his theory (Vol. III. p. 381), declaring that, "so far as his observations have extended, the plough" (to the action of which I had attributed the formation of these terraces) "would appear to obliterate rather than form regular systems of terraces such as he had described."

In his recently issued volume, "The Scenery of England and Wales; its Character and Origin," which was reviewed in the October number of this Magazine, Mr. Mackintosh repeats and enforces his views as to the marine origin of these terraces, with a contemptuous allusion to my "Agricultural theory" (p. 92).

Now, since the causes which have modelled the existing surfaceforms of this island have a real geological interest of no little moment-especially as the same causes, if of a geological character, were no doubt at work very generally throughout the world during the same period, and as those to which Mr. Mackintosh assigns the terraces in dispute indicate a very recent emergence from the sea, and elevation of the entire island by at least a thousand feet; and also that this process took place through a series of slight steps or jumps locally of a few feet at a time, corresponding to the intervals of height between the numerously repeated terraces,-the question becomes one not of mere controversy between individual geologists, but of some importance in its bearing on general geological history. This consideration will, I hope, be my sufficient excuse for once more calling attention to the matter in dispute between Mr. M. and myself. I must refer the readers of the Magazine to my paper already mentioned (July 1866, p. 293) for the arguments employed by me in support of the agricultural origin of these terraces, popularly called Lynchets, or Balks, being unwilling to repeat them here. But as Mr. Mackintosh reproduces his theory of their marine origin in his present volume, with some additional illustrations and examples, I will quote some passages from that work in order to show the extent to which, if adopted, it would carry us, appending as we go on a few brief comments.

In p. 85, he instances "the successive levels of the Brent knoll and its connected platform as "terraces of marine erosion, which could never have answered any human purpose," but which may be explained by "the action of a not very powerful sea, at different tidal levels, during a gradual rise of the land." How or why these levels could not have answered the purpose of facilitating the culture of the steep slope-especially to the population which at one period encamped for safety on the summit of the knoll, Mr. M. does not explain. He proceeds to say, "In the adjoining district traversed by the Glastonbury and Temple Combe Junction, a geologist becomes bewildered among the thickly crowded variety of these denudational phenomena. Among them he can here and there discover single terraces and sets of terraces, nearly all corresponding to the outcrop of the strata, and therefore not artificial."

Why so? If the outcrop of a stratum or series of strata of rock harder than the rest, on the slope of a hill, be tolerably horizontal,

it would follow as a matter of course that the softer surfaces of the slope, above and below it, will have been preferably subjected to aration, and in time the ordinary result would appear in the accumulation of a considerable depth of silt and gravel-the washing of the plough-disturbed surface above-on the brow of the harder stratum, while its base would be eaten away through the action of the plough, and the loss by descent to a lower level of the matter so disturbed; thus by degrees a small cliff or bank (balk) would be formed, chiefly consisting of hard rock, between the upper and under arable terraces. And this surely must be called an "artificial terrace," though the occurrence of a hard stratum of "natural" rock directed the operations of the plough. Indeed, it is obvious that in all cases of the alternation of harder and softer groups of horizontal strata in a hill-side, the agriculturist would follow the direction of the softer portions in ploughing the slope, leaving the harder as banks to support his arable terraces, just as the vinegrowers of the sunny slopes of France, Germany, and Italy, avail themselves of the outcrop of harder strata to assist the formation of the walls which support the "artificial" terraces, built up by them to check the descent of soil from above.

Mr. Mackintosh tells us in his preface that he has never been out of this island. It is therefore probable he is not aware of the extent to which the cultivation of hill-slopes by the system of artificial terraces is practised throughout the continent, nor of the general character of such terraced slopes. Otherwise, I think, he would hardly have presented his readers with the example of "Terraces of Marine Erosion," of which the accompanying woodcut is a copy (p. 88).

FIG. 1.-PROFILE OF TERRACES ON THE SIDE OF A CHALK HILL Near Twyford.

On this he remarks-"Unless we can conceive of our ancestors having been endowed with so great a taste for the picturesque as to dig out chalk for burning in a series of ornamental steps or shelves, I can see no agency likely to have formed these terraces excepting oceanic currents, at different levels, with or without floating ice" (!). As a "pendant" to this example of a steep-terraced hill, I copy one other of Mr. Mackintosh's cuts representing "the most regular series of terraces I have yet seen in the Chalk district, which occurs on the side of a hill to the south-west of Stockbridge, the slope being so

very gentle that there could have been no inducement to break it up into terraces as a means of facilitating cultivation."

FIG. 2.-TERRACES NEAR STOCKBRIDGE.

It was to meet such cases as these of gentle slopes so terraced that, in my paper above-mentioned (Vol. III., p. 293), I suggested the probability that each of such terraces might have been in early times strips of land held by separate occupiers (as was up to a very late period the custom in many "common fields," and is at present through a large part of France), the "bank" having been originally perhaps only a grassy border, or a slight fence, either of which would be enough to arrest the descent of silt during rains from the surface of the ploughed strip above, and by its long-continued accumulation upon this edge raise there by degrees a steep bank, while the slope above would, by the same process, rise into a nearly level terrace. As a practical proof of the correctness of this theory, I stated that these banks might be observed by any long resident in the country to grow in height, and gave a cut representing one that I had myself seen wholly created within a few years by this process. I will now add another to exemplify the fact that it is by no means necessary that a fence should exist along the lower edge in order to stop, by its resistance, the descent of silt, gravel, etc., from the slope above. I could adduce numberless instances in which, when there did exist such a fence, the silt has been deposited in a bank stopping short, and leaving an interval like a ditch, of a yard or two wide, between itself and the fence below. It happens in this wise (see Fig. 3),

FIG. 3.--TERRACE AND BANK CAUSED BY DESCENT OF SILT, ETC.

d

A, B represents the profile of a hill slope, towards the base of which a fence,-say a stone wall, C, D separates the arable field в, E from the one below A, D; the dotted line D, F, represents the original surface. But by the continued ploughing of that surface in horizontal furrows, aided by the wash of the disintegrated soil during rains, much of it has been carried down to form the bank and terrace, D, E, F, at the bottom of the field. The descending silt, however, does not actually

reach the wall, for the reason that the plough never can be driven within a few feet of it; a small strip of unploughed and consequently grassy surface will always intervene between the last furrow and the fence, and however slight this obstruction, it is sufficient to check the descent of silt, and cause it to accumulate in the lowest furrow. By repetition of this process through a series of years, the bank is formed, maintaining a certain distance from the wall, as seen in the woodcut. And thus, it will be perceived, that the bank and terrace above, would be produced equally, whether a fence existed below it, or only that the lowest limit of aration was originally marked by a grassy ridge, a few inches in height.

All this minute explanation of the humble origin of these banks, is, however, mere moonshine to Mr. Mackintosh, who prefers to bring the ocean up to and above the tops of our Chalk and Oolite hills, to account for the petty features with which their sides are scored. It is true that in his recent volume (p. 88) he seems, though in an equivocal manner, to admit that some of the banks, terraces, etc., may have been formed artificially; while in his earlier paper he denied this origin to any. He now only ventures to say, It is, I think, by (marine) currents acting on an easily moulded material, that many of the terraces of the chalk downs can be most satisfactorily explained." This, of course, makes the intervention of the ocean, and consequently the recent elevation of the surface of the island from beneath it, just as indispensable as if all the terraces were ascribed to its erosive action. So that nothing is gained by the evasive admission. Only a perplexing doubt is introduced as to which of the "thousands of terraces to be seen at different levels on the hill-sides of Wiltshire, Dorset, Hants., and other of our counties, are to be ascribed to the work of Giles Ploughman, and which to mighty Neptune. They were all "raised sea-beaches" in Mr. Mackintosh's paper of July, 1866, now some are, and some are not! I venture again to maintain that all are of artificial origin; and that consequently no proof is to be derived from them, either of the very recent sojourn of the sea upon the summits of our hills, or of the " very limited amount of atmospheric denudation in the Chalk and Oolite districts," which was another most important inference drawn from these terraces by Mr. M. (Vol. III., p. 69). They, in truth, lead to the very opposite conclusion, showing indisputably how largely atmospheric influences have altered the form of the surfaces exposed to them, within periods of a very few years' duration. It is hardly worth while to notice some futile objections urged by Mr. Mackintosh to the agricultural orgin of the terraces, such as that the strips of arable could not have been held "in severalty," because such divisions are not mentioned in title-deeds, etc.; whereas it is notorious that nearly all old terriers of estates contain mention of single acres, half-acres, or other small quantities of land, so held in the common arable fields of the manor. But, of course, in suggesting the possibility of the terraces having in some cases originated in their having been held in early times by different culti vators, I by no means intended to suppose this to have been the

fact in all cases. Probably also many such terraces were intentionally formed by the farmers, with the pick-axe, with the object of preventing the descent of soil to the bottom of the hill, and of widening the arable surface; as is constantly done by the continental cultivators of similar slopes. Again, Mr. Mackintosh says, "Many farmers have assured me that there is now, and has long been, a general desire to plough down the lynchets,' and that formerly their number was much greater than at present" (p. 89). No doubt, in the course of time, as two separate strips, "or lands," become united in one estate, or held by the same tenant, it would be for his interest to "plough down" the bank between them, which, being composed chiefly of the finest mould, washed down in preceding years from the slope above, would enrich the impoverished land at its base. And, indeed, this occasional "ploughing down" of the banks accounts satisfactorily for their partial disappearance on some points, as well as their "gradation into the more general slope of the ground," which naturally seems to have "bewildered" Mr. Mackintosh, on the assumption of their marine origin. But, supposing the banks to be "marine terraces," and, therefore, often composed of shingle and shells, this "general desire to plough them down," would be unaccountable. In truth not a single example of a terrace so composed has been produced by Mr. Mackintosh, and I venture to assert none such will ever be found in the situations indicated in his theory.

We all know what a sea-beach is. The Chesil bank is an admirable example. There is another stretching eastwards, along many miles, from the base of Beachy-head to Hastings. They are composed, like all sea-beaches, I believe (differing in some respects from flat sandy shores), of rolled pebbles or boulders, with or without an admixture of sand, broken shells, and other sea-wrack. Has Mr. Mackintosh examined any of his "raised sea-beaches" and found them, or even any one of them, to be so composed? Not one! Has he produced a single sea-shell found in any of them? Not one! Throughout his whole description of these numberless banks and terraces, I cannot find that he has even attempted to examine the composition of any-with the single exception of one of a "Series of Terraces near Llangollen," "the finest series of undoubted Old Coast-lines or raised Sea-beaches I have yet met with, on the face of a hill to the south of Llantysilio railway station-the highest terrace reaching an elevation of at least 1500 feet." One of these, close to the railway station, Mr. Mackintosh did examine (I presume while the train was stopping, as he says "I had not time to make a particular examination")-but "it seems covered with fine clay, mixed with small stones, some of which are much rounded, and, where the soil has been thrown up by moles, it appears mixed with the refuse of decayed shells "-land shells, no doubt. And this is the sole fact or observation relative to the composition of these "innumerable raised sea-beaches," which Mr. Mackintosh affords his readers, if we except the statement that "Mr. Codrington, F.G.S., and others, have ascertained that a number of the terraces have a deposit of ap