98 
On the western flank of the hills the direct evidences 
of its action are plentiful ; but on the eastern slopes no such 
evidences are observed further south than the valley of the 
Aire. Deposits of till or glacial mud, containing scratched 
boulders, are frequent in the valleys of the mountain limestone 
district north of the Aire. An example may be seen near 
the Skipton station on the Midland railway ; numerous others 
have been exposed in the new line from Settle to Carlisle ; 
and a very interesting bed has been exposed in the exploration 
of the Settle Caves. Besides these remains of the ancient 
glaciers in the valleys, traces of glacial action are found on 
most of the hills. Their summits are found scratched 
to the height of many hnndred feet. Their slopes have been 
rounded, and a lateral moraine occasionally deposited ; and 
numerous blocks, weighing in some case§ tons, have been 
left by the ice, perched in all kinds of positions, on the tops 
or sides of the hills. These blocks, in most cases, are com- 
posed of rock not found in the district, but have been 
transported many miles from their original position. All 
these evidences indicate a period when the country was 
covered by great glaciers. The scratches and stride generally 
have a tendency to an easterly direction, and indicate that 
the Yorkshire branch of the main glacier from the Cumberland 
district has travelled over the high lands composing Stainmoor 
Forest, and thence proceeded in a south-easterly direction 
down the valleys of the Swale and Ure, ending possibly 
in the low lands of the vale of York, where great quantities 
of debris would be deposited by the melting ice. 
Turning again to the district through which runs the 
river Calder, we find none of the direct evidences of glacial 
action. There is no till or stiff glacial clay, containing scratched 
boulders, and, so far as I am aware, no striae have been found 
on the hill tops; though, if any existed, they have had a 
good chance of being preserved beneath the peat, which is 
