KENDALL : THE GLACIER LAKES OF CLEVELAND. 
3 
westerly slopes. In the Vale of Pickering these deposits do 
not rise above 350 feet, and at the western end appear to be 
composed entirely of local rocks. 
Along the escarpments overlooking the Vale of York drift 
does not occur much above 600 feet. Southwards it declines in 
elevation, and may be said to terminate in the two fine moraines 
of York and Escrick. 
Glacial stria? have been found near Saltburn running N.W. 
and S.E., and at Roker, near Sunderland, from E.N.E. At 
Filey striae have been recorded striking from N. 20° E., and 
N. 24° E.. at Bayness (R.H. Bay) due N., and at Sandsend 
X. 35° W. 
The Ice-Sheets. 
There do not appear to be any evidences of the presence 
of the sea in the Cleveland area during the Glacial Period. The 
occurrence of shells, chiefly fragmentary, is most probably 
due to the invasion of the country by the edge of an ice-sheet, 
which advanced on to the land after traversing a sea-floor strewn 
with shell -banks. Profs. Garwood and Gregory's observations 
on the Ivorv Gate Glacier have dissipated in a decisive way 
the objections against the possibility of a glacier transporting 
marine shells from deposits over which it passes, and the same 
observers have shown that materials thus picked up by a glacier 
can be transported to a higher level than the bed from which 
they were derived. 
Tlie evidence obtained in the district proves that we have 
to do with three great ice-sheets moving on the Cleveland area 
and combining in its glaciation. 
I. — The Western Sheet. — This seems to have been the first 
to reach Cleveland. At this time the Irish Sea basin was filled 
with ice, forming a sea of ice which sent off a great glacier up 
the Solway, which, being joined by a glacier from the Southern 
uplands of Scotland, and by another from the Lake District, 
filled the Vale of Eden to overflowing. One immense ice-stream 
overflowed the Tyne watershed and invaded Xorthumberland, 
whilst another great glacier crossed by Stainmoor Pass into 
Teesdale, where it was joined by the Teesdale ice. This great 
ice-stream passed down Teesdale to the coast, and perhaps 
