EXCURSIONS. 
413 
The Chairman referred to the great loss which had been 
sustained by geological science by the deat]i of Dr. Henry Clifton 
Sorby, and referred to the pioneer work done by him in many 
branches of science. 
Two new members were elected. 
Mr. Joseph Lomas, A.R.C Sc., F.G.S., then gave an address 
on the structure of the Berwyn District. 
He described the Berwyns as a great dome some 300 square 
miles in area, and consisting for the most part of rocks of Bala 
age, with numerous Igneous rocks, both contemporaneous and 
intrusive. 
The dome was described as the result of successive folding 
movements along lines parallel to the Caledonian axis, north- 
east to soutli-west, and the Pennine axis, north to south. 
To the north-west of the dome and separated from it by 
the Bala Fault, lies a great sj^nchne occupied by Silurian rocks. 
This fault, where it crosses some of the anticlines, has been 
stated to have a throw of 13,000 feet, but where it enters the 
synclinal areas this dwindles to 4,000 feet. 
The fault is pre-Triassic, and corresponds in direction and 
alignment with the Anglesark anticline, and it can be shown, 
in common with many of the larger dislocations in Britain, to 
have moved during several geological periods. 
In this instance a pre-Carboniferous and also a post-Car- 
boniferous movement can be demonstrated. 
In dealing with the igneous rocks of the district, Mr. Lomas 
stated that some of them, appeared to be of contemporaneous, 
while others were certainly intrusive. 
As the succeeding paper was to deal with the Carboniferous 
rocks, Mr. Lomas did not treat of them in any detail. 
In the discussion, Dr. Dwerryhouse pointed out that in at 
least one instance, viz., that near Glyn which was visited that 
day, there was a case of contemporaneous volcanic activity. 
This could be seen from the occurrence of a bed of ash with 
fragments of Bala Limestone and of a neighbouring Felsite. 
The discussion then turned to the question of how far 
torsion structure had entered into the tectonics of the district, 
and this led to some discussion of torsion structure in general, 
L 
