Vol. 55. | THE RIVER-SYSTEM OF SOUTH WALES. 295 
direction had. occurred along the Welsh Border, as observations in 
Shropshire seemed to indicate ; butit was probable that much of the 
folding along this tract took plave in Old-Red-Sandstone times, and 
therefore at an earlier date than that of the Hercynian folding. 
As to the faults showing a ‘Charnian’ direction, the speaker 
would like to ask whether, like the different systems of parallel 
folds, they might not be of various ages. 
Mr. A. E. Satrer thought that this interesting paper had brought 
out two most important points to students of post-Pliocene geology : 
firstly, the action of long-continued earth-movements which have 
affected the drainage-systems of Southern and Central England; and, 
secondly, that subaérial denudation has taken place on a large scale. 
The presence at high elevations north of the present Thames Valley, 
of débris from the Lower Greensand of the Wealden anticlinal 
which can be traced from Hampstead, Barnet, etc., right across 
Southern and Hastern Essex to Walton-on-the-Naze, pointed to an 
accentuation of the east-and-west (Armorican) folding in com- 
paratively recent times. 
The Author did not seem to have taken the Oolitic escarpment 
into serious account. As this was on a grander scale than that of 
the Chalk, it appeared to deserve more consideration, especially as it 
could be shown by its outhers to have had much influence on the 
formation of the Severn-avon Valley. He noted that the syncline of 
the Thames Valley was stated to have been initiated in post-Oligocene 
and pre-Pliocene times; and wished to enquire whether the presence 
ot Lower Plocene fossils at Lenham (600 feet above Ordnance datum) 
did not require a later age to be assigned to them. 
Mr. Greenty observed that evidence as to the relative ages of 
movements along Caledonian and Charnian lines was obtainable in 
the Anglesey region within an area of quite moderate size. The 
dominant strike of the Carboniferous and various older rocks was here 
north-east to south-west, or Caledonian; but the lines belonging to 
this series were cut and shifted by a considerable number of fractures 
haying a north-westerly to south-easterly, or Charnian trend. The 
dykes also of the series, regarded by the speaker as probably of 
Tertiary age, ran in the same north-westerly to south-easterly 
direction ; and, moreover, often coincided with lines of displacement. 
Finally, in the Central area, dykes with this trend were broken 
and shifted by still later north-easterly to south-westerly, or Cale- 
donian, fractures. It was thus clear that Caledonian and Charnian 
movements had occurred alternately one with the other, within the 
limits of what is now the island of Anglesey. 
Mr. P. Laxe said that he was somewhat surprised to find that the 
views of the Author were so similar in many respects to those which 
he had himself advanced two years ago concerning the development 
of the rivers of North Wales; views which were at the time adversely 
criticized by the Author. Hewas completely in agreement with the 
Author in believing that the north-east to south-west valleys were 
directly determined by earth-movements, and that the other river- 
valleys were not so determined; and he looked upon the valley of the 
