Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/402

 tish earthwork, or rather by what remains of it, as about half has been lost from the gradual wearing backward of the cliff. When this work was made, the ground must have reached much further south than now, in the form shown by the dotted line in fig. 2, as such works are always on hills.

The fort was far from finished when I saw it ; but the unfinished western ditch gave some sections of gravel and loam above and sometimes wedged into the clays of the Woolwich Beds, as in figs. 3 & 4, which represent part of the same pipe (fig. 3 the western side, and fig. 4 the eastern).

3. General Remarks.

The Dieppe section seems to show a sort of passage from the Oldhaven Sand up into the London Clay, layers of sand occurring in the latter. There is also sand in the same position at Newhaven, where, however, the Oldhaven Beds are not present.

The sections show the extent of the same beds (insignificant as they are in thickness), or of like conditions, in the Lower London Tertiaries, — the Oldhaven Sand of Dieppe (3) being just like that of East Kent*, the shelly clays of the Woolwich Beds both at Dieppe and Newhaven (5) being the same as those of West Kent (with estuarine shells† of, the thin bed of lignite, peaty clay, or firm sand that occurs throughout Kent occurring also in the sections above described (6), and the lowest sand at both (8) seeming to be the same as that which forms the whole of the Woolwich Beds in East Kent, and occurs in West Kent also‡.

The mottled plastic clays are absent ; and the bottom-bed (9) consists of flints partly rolled, as is elsewhere the case where it rests on the chalk — and not of flint-pebbles, as where it rests on the Thanet Beds.

Discussion.

The Chairman (Prof. Morris), in inviting discussion, called attention to the existence of Tertiary beds of similar character near Epernay and Rheims, and in other parts of France.

Mr. Evans remarked on the bearing which this extension of soft, yielding strata had on the excavation of the Channel. The disturbances in the sands and clays might be due to the springs having formerly, owing to the distance of the sea and the river- valley not having been excavated, stood at a higher level, and having thus softened or washed away the bed beneath the gravels.

Mr. Pattison mentioned that in all the combes along the French coast towards Treport there were traces of soft Tertiary beds and blocks of sandstone.

Mr. Whitaker, in reply to a question from the Chairman, stated that, to the best of his belief, the sandstones at Dieppe were not calciferous. The sands were above the Woolwich beds, and therefore not Thanet sands.


 * Quart. Journ. Geol. Soc. vol. xxii. p. 410 (bed 3).

† Mr. Prestwich has given a list of the fossils found at Newhaven. ‡ Quart. Journ. Geol. Soc. vol. xxii. p. 409 (bed 2).