valley between Blackford, and Braid. The scratches are not "in a direction approximating to horizontal," for they have various inclinations from horizontal to 60°. The direction of the scratches cannot be "nearly east and west," as stated by Mr Milne Home, for the dressed surface has a direction nearly from N.W to S.E., and faces the S.W. The protuberances or irregularities of the abraded surface are all rounded on the N.W. side, giving unequivocal proof that the abrading agent acted from that quarter. Even assuming that the gravel and sand were not originally the abrading agents, the statement of Mr Milne, that these "must have been brought from the eastward," is improbable, when the position of the face of the cliff, as already noticed, and the materials of the mass are kept in view. The sand is very distinctly stratified nearly horizontally or slightly inclined, and adheres with considerable firmness to the surface of the rock. It is a natural concrete, the particles being held together by carbonate of lime, probably due to infiltration. In some places the abraded face is nearly vertical, in others it slopes northwards underneath the projecting mass at an angle of 50°.

The abraded surface has not been acted upon uniformly, like the dressed ones which have now been considered. It exhibits an irregular series of dimples with shallow grooves of small extent, as if the abrading agents had been subjected to frequent shiftings and intermittent pressures. While some of these acted on the vertical face, others have been squeezed under the projecting cliff, and have escaped by a downward course, Floating ice and driven gravel may, in conjunction, have furnished such a result, but I feel warranted in concluding, that, if the examples of dressed surfaces which have been enumerated, were produced by glaciers or icebergs, the Blackford hill example is not entitled to a place among them. It seems to be a local phenomenon, connected with the Braid burn, and is probably of more recent formation than the dressings.

Several years before the description of this abraded surface by Mr Maclaren and Mr Milne Home appeared, but overlooked

by these authors, Mr Rhind had referred to the phenomenon, and unhesitatingly indicated its mode of formation :-"The clinkstone, in a liquid mass, has evidently fallen on the bed of sand; for it presents the identical appearance that a similar mass of melted iron, when run upon sand would do. It is moulded into a round form, and leaves waving depressions on the sand. That portion of the sand, for about the thickness of a foot, in immediate contact with the clinkstone, is hardened into stone, and, when broken off, retains the impression of the rock above, without adhering to it closely." (Excursions, p. 61.) We refrain from commenting on such description and explanation.

The young observer should be on his guard against being deceived by different kinds of weathered surfaces, such as may be observed at almost every quarry. When the exposed portions of the rock have been acted upon by river currents, drift sand, or sea gravel thrown up by storms, the abrasion may be great, but will present an irregularity very different from the obvious levelness of a dressed surface. The exposed ends of the strata at the new quarry at Granton, where this spurious appearance was recently displayed, may be studied with advantage, for they have successfully deceived even experienced geologists.

Before leaving this part of the inquiry it may be noticed, that the craig and tail, and the dressings, coincide in their indications of the abrading agent having acted from the west. The other effects which it, produced now require to be investigated.

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CHAPTER IV.

Reluctance of Observers to study the recent Deposits-Classification of the matter resting on the Dressed Surfaces-The Staple of Walker-Diluvium and Alluvium of Phillips and Conybeare-Diluvial, Ante-diluvial, and Post-diluvial of Buckland-Eocene, Miocene, Older Pliocene and Newer Pliocene of Lyell-Superficial Deposits of Mr Home.

Satisfactory evidence seems to have been produced to prove that the direction of the valleys and the shape of the hills plainly indicate an impetuous body of water moving and acting in an easterly direction; it may be at various and distant intervals. Proof has likewise been furnished that substances capable of scratching the solid rocks have been pressed along their cropping, and have left an even and rutted surface, with the ruts indicating the force to have acted from the west. These coincidences being recognised, we have now to consider what has become of the detached matter and the rubbers which were the agents of the abrasion. But this inquiry necessarily involves the consideration of all the stratified or unstratified materials which rest on the dressed surfaces, and to what extent these materials were derived from the operations of that destructive agent, to which we have already so frequently referred, either immediately or remotely. Nay more, have the strata, between the dressed surfaces and the present soil, a uniformity of structure and material; or are there any proof of different agents having operated, and with intermittent energies, as displayed among the older deposits? These questions are of deep interest, because not a few observers, while admitting a great diversity of structural character among the materials resting on the dressed surfaces, have usually made their selection, and while pleased with their explanation of the origin of certain beds, have, strangely enough, disregarded the vast amount of

other materials left out of view. Besides, the deposits have been classified by empirical rules, and denominated by hypothetical terms, calculated to retard the study of perhaps the most interesting group of strata constituting the crust of the earth.

Upwards of thirty years ago, when referring to the changes which had taken place in our Fauna at or subsequent to these events, I remarked, that "It is customary with antiquarians in general, to delight to dwell on scenes which exhibit to their imagination the memorials of events nearly forgotten, or the transactions or customs of distant ages. Events of a more recent kind, or transactions which may be considered only in progress, do not arrest their attention, or, at least, fail to excite in their minds that deep interest which remoter subjects readily awaken. The public likewise feel and act much in the same manner. There is an importance attached to remote events, depending solely on their antiquity; while there is a vulgarity inseparable from recent events founded on the supposition of their being well-known. Geologists have long acted, and we fear still act, in a similar manner to antiquaries. The study of the character of the older strata (their position, structure, and ingredients), has been pursued with greater ardour than any researches which have been entered upon with the view of illustrating the connections of the newer deposits. Coal, sandstone, and limestone have been examined with zeal, while few have bestowed their attention on peat, sand, or marl. Similar practices have prevailed with regard to organic remains. Many have speculated concerning the structure and habits of those relics which occur in the solid strata, who have not deemed the study of the laws which regulate the living races, an object of much importance."

"We are not disposed to refer these well-known habits of the antiquary and geologist to any natural preference of the obscure to the extinct,-of subjects the relation of which, circumstances have rendered us incapable of determining, to those of a nature which may be illustrated with certainty. We are aware that antiquarian and geological speculations are usually

engaged in from motives of amusement, and, when conducted in the usual manner, seldom fail to gratify their votaries. Were they to commence their investigations with a knowledge of recent events, and proceed by degrees to those of remoter times, their conclusions would assume a more imposing character, but the accompanying labour would be greatly increased. In speculating on the affinities of recent events, the understanding is ever occupied with facts; the imagination, thus in trammels, dare not indulge in its licentious wanderings. But when remote events are the subject of our contemplation, fancy becomes a valuable assistant by reuniting disjointed links, supplying that which is wanting, and enabling the mind to arrive at conclusions, which, without the labour of investigation, had probably been long anticipated." (Edinburgh Philosophical Journal, October 1824, p. 287).

These views, which were expressed in earnest, met with a very unwelcome reception, especially from those whose soaring hypothetical propensities they were intended to restrain. Nor at the present hour do the remarks seem uncalled for, since geologists are not agreed as to the principles of the nomenclature of the materials resting on the dressed surfaces, their relative antiquity, or the agents which were concerned in their dis tribution.

Dr Walker, professor of Natural History in the University of Edinburgh, to whom we have already referred, with all the respect due to great attainments, treated in his Lectures of STAPLE, or what is at present denominated soil, and also of the "loose superficial nodules" termed " BOULDER-STONES," better known at present as Erratics. At a later period, and at the date, in 1822, of the "Outlines of the Geology of England and Wales," by Conybeare and Phillips, the belief was all but universal, that a large portion of the materials covering the dressed surfaces, and even the dressings themselves, were generated and distributed by the Noachian deluge. Hence the division of these superficial deposits into DILUVIUM and ALLUVIUM, the former indicating the products of the FLOOD, the latter, materials of more recent origin.