90 KENDALL : NOTES ON SUPERFICIAL GEOLOGY OF THE VALE OF YORK. 
belonging to the western drainage, such as Granites from Galloway, 
Brockram and the Dufton ''Granite" from the Vale of Eden, and 
various igneous rocks from the Lake District, such as the remarkable 
diorite or gabbro of Carrock Fell, the quartz-porphyry of Threlkeld, 
and most notably the well-known granite of Shap Fell. This glacier 
gathered other characteristic rocks, such as the Whin Sill, in its 
passage down to the'Jow grounds, and at one or more stages of its 
history it debouched into the North Sea. 
While these events were in progress a great sheet of ice was 
advancing upon our east coast from Scandinavia, which doubled back 
all the native ice streams, turning some coast-wise to the northward, 
others to the southward, while yet others, probably including the 
Teesdale stream, were deflected into inland courses. Either the 
deflection of the Teesdale glacier was brought about in this manner, 
or the true explanation of the fact is that the Norse ice was already 
obstructing the mouth of the Tees when the native stream reached 
sea level. In either case the Teesdale glacier was driven over the 
watershed into the drainage valley of the Ouse and received a series 
of tributary glaciers flowing along the great dales down to aud 
including Swaledale. 
How far the stream ultimately extended has not been definitely 
ascertained, but it certainly reached several miles beyond the city of 
York. 
The excursions on the 26th and 27th April will be made to view 
two magnificent terminal moraines, the finest in the British Isles, 
which mark phases in the retreat, or possibly of the advance, of this 
glacier. They extend as perfect and nearly parallel crescentric 
mounds nearly from the foot of the Wolds round to the outcrop 
of the Magnesian Limestone. 
York stands a little to the western side of the centre of the 
more northerly moraine, and on the first day's excursion the westerly 
limb will be visited. Sections are visible on the mount at York and 
in the neighbourhood of Bilbrough. They show, besides the more 
characteristic dirty, clayey, moraine-stuff, fairly clean, well-washed 
gravel, yielding characteristic erratics. Beyond Bilbrough where the 
side of the glacier seems to have received a chock from a boss of 
