328 Notes and Comments. 
GLACIAL GEOLOGY OF THE WESTERN SLOPES OF THE SOUTHERN 
PENNINES. 
Dr. Albert Jowett dealt with the area extending from 
Blackstone Edge southwards to the southern extremity of the 
Pennines. No striated surfaces of solid rock have been dis- 
covered at high levels, and the two that have been recorded at 
Salford and Fallowfield serve only to indicate a general move- 
ment from N.W. to S.E. For more detailed information as to 
the movements of the ice-sheet, the only evidence is that 
afforded by the distribution of the drift at high-levels and by 
the systems of drainage along the edge of the ice. From this it 
may be inferred that the main directions of ice-movement about 
the time of the maximum extension of the ice-sheet were 
roughly towards the north-east in the Tame valley, the east in 
the Etherow valley, and the south-east and south-south-east 
in the Goyt valley and further south. These directions were 
much modified locally by the complicated configuaration of the 
sub-glacial surface. The first barrier of hills met with on 
approaching the Pennines from the South Lancashire and 
Cheshire plain was almost everywhere overridden by ice, which 
left definite deposits of drift with foreign rocks at altitudes up 
to 1,360 feet, and scattered erratic boulders up to 1,400 feet. 
As this foreign drift penetrates further into the hills its maxi- 
mum. altitude falls steadily. It has only been traced across the 
main Pennine divide at the broad col (1,100 feet above O.D.) 
south-east of Chapel-en-le-Frith. 
ERRATICS. 
Thick deposits of drift and big erratics are comparatively 
rarely met with at the extreme limit of the foreign drift, 
towards which the erratics generally diminish in number and in 
size. Boulders of local rocks, often obviously transported 
and uplifted beyond their parent outcrops, become relatively 
more abundant towards the limit of the foreign drift, and 
generally form a spread of drift extending beyond it and passing 
insensibly into the driftless area. Great lakes were held up by 
the ice-barrier some time after it commenced to retreat from 
the western slopes of the Pennines. During early stages in 
this retreat the drainage from the lakes in and north of the 
Etherow valley excaped northwards, and ultimately passed 
through the Walsden gap into the Calder. When the ice- 
barrier east of Manchester fell below 600 feet above O.D., this 
drainage followed the course of that south of the Etherow 
valley and escaped southwards. The action of the ice-sheet 
with its associated streams of water, together with the marginal 
water derived from melting ice and draining from the region 
beyond the ice-sheet, assisted by the action of post-glacial 
streams, in depositing the original drift, in cutting new channels 
Naturalist, 
