SECTIONAL TRANSACTIONS.—C. 477 
Friday, September 8. 
Discussion on St. George’s Land and the shore-lines of the Midland 
Barrier during Carboniferous times (10.0) :-— 
Prof. W. S. BouLTon. 
Name proposed by Jukes-Browne for the continuous tract of land in 
early Devonian time extending from Wales across St. George’s Channel to 
eastern and central Ireland. Prolonged erosion of this part of the Cale- 
donian continent was followed by submergence ushering in the Carboni- 
ferous. ‘The delimitation of St. George’s Land during this period is the 
main subject under discussion. 
Repeated oscillatory movements during the Carboniferous and Permian 
shifted the shore-line, so that it is necessary to refer the land margin at any 
place to the particular time-division when it so stood. The ‘ Mercian 
Highlands ’ of Midland geologists are the eastern extension of St. George’s 
Land. 
A map is exhibited showing the shore-lines in early Tournasian and late 
Viséan times, and also the areas where Millstone Grit (sensu stricto) and Coal 
Measures were presumably not deposited. ‘The points specially referred 
to are: 
(1) The advance of the shore-line northward followed by retreat south- 
ward in the South-West Province during the Avonian, and the southward 
advance in the Midland Province during the Viséan. 
(2) The land boundaries in the Leicester area deduced from outcrop and 
borehole evidence. A possible sea connection west of Leicester between 
the Midland and South-West Provinces in Viséan time. 
(3) Evidence from the pebbles and breccia-fragments of Permian 
(Enville) beds points to eroded Avonian under the Triassic cover of the 
Midlands. 
(4) A brief summary of evidence from borings as to the extent of con- 
cealed Coal Measures between the Birmingham and Leicester areas. 
Mr. E. E. L. Dixon. 
St. George’s Land appeared in Caledonian times, and during the deposi- 
tion of the Upper Old Red Sandstone (Farlovian), its southern slopes 
extended at least as far north as Brown Clee. Subsequent changes on its 
northern side differed from those on the southern, and resulted in a southern 
shift of the barrier, the northern side being progressively submerged, whereas 
to the south land gained on the sea. The changes were due largely to con- 
temporaneous earth movements, but the retreat of the sea on the south was 
helped by the deposition of grits on the margin—the Cornbrook and 
Drybrook Sandstones of Titterstone Clee and the Forest of Dean respec- 
tively. The barrier was greatly enlarged by the mid-Carboniferous upheaval. 
On the northern side the later depression which brought about the deposi- 
tion of the true Millstone Grit (Namurian) and Coal Measures commenced 
much earlier in the more central parts (N. Staffs., etc.) of the Midland basin 
than near the barrier (S. Staffs., etc.).. The contrast in this respect between 
neighbouring coalfields is so great as to suggest that the depression included 
contemporaneous northward down-faulting between the contrasting coal- 
fields. The southward encroachment of the Midland Province was only 
checked by the mid-Carboniferous upheaval, and when sedimentation was 
resumed it extended over what had formerly been part of the South-Western 
