The aim of this paper is to offer an explanation of the phenomena intimately related to the sculpturings of the Chalk Downs in the district under review, namely:—

(1)The Dry Chalk Valleys.

(2)The River System of the Wealden area, as far as it relates to the Chalk Downs.

(3)Incidentally, the Denudation of the Wealden area.

More than twenty-three years have now passed since Dr. Kidston published his memoir on the fossil flora of the Somerset and Bristol Coal-field, and in the meanwhile no further additions to our knowledge have been made. Kidston's paper was chiefly concerned with the plant-remains of the southern or Radstock portion of the basin. Those from the northern or Bristol area have only been studied incidentally. This would seem quite natural on account of the greater size and industrial importance of the Radstock Coal Series, and from the fact that this locality has been long known to yield the finest and best preserved impressions of fossil plants to be found in any coal-field in the British Isles. The collieries in the Bristol district are comparatively few and smaller, fossil plants being much scareer and less well preserved.

During the autumn of 1909, I made a short excursion into the Bridgend district and examined the Avonian sequence near Llantrisant. The present note embodies the results of a few traverses and suggests a correlation with the sequence already established at other points of the South-West Province.

“In a trough from 2 to 10 kilometres wide and 100 to 300 metres deep lies the Nile, meandering through a flood plain formed by yearly deposits of silt brought down from the Abyssinian table-land by the Blue Nile and the Atbara. This trough was determined in the first instance by fractures of the crust which caused a strip of country from about Edfu (lat. 25° N.) to Cairo to be depressed, leaving the plateau standing high above it, just as the Red Sea and the gulfs of Suez and Akaba were formed, probably about the same epoch. This interference with the drainage of the country doubtless produced a series of lakes in the low-lying area, while the drainage of the eastern plateau commenced to excavate the valleys which now exist as dry desert wadies, their development being in many cases far from complete, as shown by the cliffs which interrupt the slope of the valley when a harder bed of rock than usual is met with.

Zoœcia roughly elliptical, length ·60 to ·68 mm., width ·36 to ·40 mm., length of area ·36 to ·40 mm., width ·24 to ·28 mm.; they have broad side walls, whose upper surfaces slope slightly to the area; at the foot there is generally a fair amount of external front wall, which often carries its own accessory avicularium or the oœcium of the preceding zoœcium; the walls of adjacent zoœcia are always distinguishable and very often not in contant.

In September last I discovered a number of plant remains in the Carboniferous Limestone at Meathop Fell, Westmorland, amongst which were several fragments of what, at first sight, looked like a species of Lepidodendron. A closer examination, however, of one or two of the better preserved specimens, which showed traces of leaf-scars, at once suggested Archœsigillaria Vanuxemi, specimens of which I had previously seen in the Kendal Museum.