^{page 169 note 1} This pitching or being on edge of the blocks and fragments of the “re-arranged glacial drift” I have observed in the drift in different places; but in none do they appear to be so conspicuous as in the co. Wexford, where they are characteristic of the Glacialoid drift, some of these drift sections being a mile or more in length. In accumulations forming at the present day I have observed blocks or fragments on edge in the following: at the bends of rivers, especially in mountain streams; in masses of drift due to landslips, where the mass has slipped outwards, and not gone down perpendicularly; and in the in-shore accumulations in estuaries, where the drift between the base of the cliff and low water-mark may have all or most of the contained blocks and fragments on edge. I can also imagine shore-ice or an iceberg pushing along on a rasas of drift would shove up the blocks and fragments. Mr. A. Wyley, late geologist to the Government of the Cape of Good Hope, thus writes on the subject:—“A solid body, such as a landslip or a moving iceberg, would, I fancy, lift stones off the flat, and set them on edge; the horizontal thrust in either case overcoming the force of gravity and acting at right angles to the same. In other words, as, under the action of gravity, flat stones arrange themselves at right angles to the force, so, in case of a force acting at right angles to the force of gravity, it is natural that the flat stones should change their position in the same degree; but as the force of gravity would still be acting, their position would in most cases be determined by a ‘component’ of the two forces. This explanation will only apply to where the mass of mud has been moved by some strong horizontal force, and may also account for the fact of the more or less upright position of slates and such like stones at river bends, where there is always a strong horizontal force in the eddy.” In the co. Wezford the upright position of the stones may in part be due to shore-ice or stranded icebergs; but it seems more probable that the drift was similarly formed to the shore accumulations of some estuaries of the present day, as all these drifts are adjoining what must have been land when the shelly drifts were being deposited, the great lengths of the sections being due to the present cliffs running with very similar, if not nearly identical, bearing to the cliffs that bounded the Pre-drift islands.

^{page 170 note 1} Off the present coast of south-east Ireland the principal current runs from south towards north; and from the headlands, bars and banks extend northward, in which the materials become finer as we proceed in that direction; while westward, or inside these bars and banks, fine materials are accumulated. On the coast south of the headlands, which are open to the full force of the current, the accumulation is well-washed sand, gravel, or shingle: and, as similar relations exist between the different deposits and the ancient islands and shore-line of the sea of the “Esker period” in this part of Ireland, we are led to believe that then, as now, the principal current flowed from southward to northward. It is commonly believed that the chalks and flints found in the drifts of the cos. Wicklow and Wexford come from Antrim in the north of Ireland. I, however, see no reason for such a supposition; for if they came thence, the drifts, as we proceed northward along the coast through the counties of Dublin, Meath, Louth, and Down, ought to become more and more chalky, which is not the case; for when we proceed northward out of Wexford, we lose all the great marl deposits, such as would be formed from the denudation of chalk. The marls of Wexford and the adjoining portion of Wicklow would seem to be the washing from some of the chalk in England or France, while the sands associated with the marls are similar to the detritus formed by marine or meteoric abrasion from the associated rocks of the greensand formation. Furthermore, the pieces of chalk found in the drift are more lite the hard beds in the English chalk, the “Chalk rock” of Whitaker, than any of the Antrim chalk. Mr. Wyley, however, who has carefully examined the counties Wicklow and Wexford, thus writes:—“That the chalk flints are from the Irish chalk, not necessarily from Antrim, is proved by the following considerations. A very large proportion of the flints are altered into jasper of various sorts; many are agates and chalcedonys, which are only found when the chalk has been subjected to strong volcanic action, as in the North of Ireland. Besides, I have in my possession a flint, picked up near Cam Point, with a peculiar coral, at once identified by the late Mr. G. V. Du Noyer as similar to ones he had seen in the chalk of the North. The abundance of these flints and jaspers at Cam Point and thereabouts, as well as in the bight of Cardigan Bay, at Aberystwith, etc., on the same parallel, simply arises from the continual tidal action grinding all into sand and mud except the flints. These I consider are all out of one of the drifts, and that not the marl; probably the old glacial drift, which, as indicated by the rock markings of the district, came from the N.W. It is barely possible, as the chalk or its equivalents extends through Belgium and Northern and Eastern France to Northern Germany and east of the Elbe in Bohemia and still further eastward, they may at one time have possibly extended to the valley between Cam Point and the Welsh coast, the present St. George's Channel. In the great limestone plain of Ireland and the Silurians and granites to the east of it there are ample materials for the formation of the Wexford marls, in which you will find, though rarely, limestone pebbles. I always looked on these marls as the deep-water representatives, of the limestone [Esker] gravels which choked up all the valleys through the mountains to the west and north-west, while the marls and clays were deposited in the shelter of the latter.”

^{page 171 note 1} This peculiar drift is often similar in aspect to the “foundation” or “broken shelf” (of the miner), made up of the underlying rock debris, found in many places between the typical glacial drift and the solid rock. In Tyrone, Londonderry, Galway, and many other places, it lies between the glacial drift and the rock, and is of inconsiderable thickness; but in some of the southern counties it is of a great thickness, and unassociated with any typical glacial drift. The rocks under it I have never found to be ice-dressed.

^{page 172 note 1} Notes on some of the Drift in Ireland, Dublin Quarterly Journal of Sciences, vol. vi. p. 249 et seq.Google Scholar

^{page 172 note 2} The faults traversing this country hare not been worked out; but I would suggest that a fault with an upthrow to the N.N.W. runs along the valley of the Bray river. This, however, would seem to be shifted and displaced by transverse faults, such as the faults in Glencullen, Sally Gap, Grlenmacanass, Glenavonbeg, etc.; while there are marked axes of elevation, nearly parallel to the valley of the Bray river, one crossing the mountains obliquely in a S.S.W. line from Laragh, while a second nearly parallel, occurs a little farther to the N.N.W.

^{page 173 note 1} It should be mentioned that on the east of the St. George's Channel, opposite to those in Wicklow, are found still higher deposits of shelly drift. The Welsh shelly drifts are, however, separated from those in Wicklow by the system of faults that occur in the valley of St. George's Channel, which is probably in the aggregate a great downthrow to the westward, as the drift in the east margin of Ireland seems to rise towards the upthrow of a fault.

^{page 174 note 1} Geol. Mag. Oct. 1865. and Mem. Geol. Survey, Ireland, Ex. Sheet 137, p. 50.

^{page 174 note 2} Paper by Oldham, T., M.R.I.A., Journ. Geol. Soc. Dublin, vol. iii. p. 195.Google Scholar

^{page 174 note 3} Geol. Mag. Jan. 1874.Google Scholar