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THE G LACTATION OF YORKSHIRE. BY PERCY F. KENDALL, F.G.S., 
LECTURER ON GEOLOGY AT THE YORKSHIRE COLLEGE. 
The address, of which the following is a rather free rendering, 
was delivered at very short notice. In its present form it is designed 
rather with a view to directing the attention of geologists to some of 
the larger problems connected with the glacial phenomena of York- 
shire than as an attempt to offer a full or final solution of them. 
1 have elsewhere* stated, somewhat at length, the grounds upon 
which I have been led to leject the theory of a great submergence of 
England and Wales during the glacial period, and to ascribe the 
phenomena to the operation of great glaciers with their concomitants 
of sub-glacial rivers, extra-morainic lakes. &c, acting upon a land- 
surface standing at about, and certainly not below, its present level. 
I have also specified the course, general effects and approximate 
limits of the glaciers so far as I had been able, either by a study of 
the literature of the subject, or in the field, to determine them. I 
may, however, briefly recapitulate the points germane to the present 
enquiry. 
The gradual approach of the ice-age produced at first small valley- 
glaciers in our great hill clusters, e.g. the Highlands and Southern 
uplands of Scotland, the Lake District, North and South Wales, the 
mountainous parts of Ireland, and perhaps some few valleys of the 
Pennine Chain. 
With the accentuation of the cold these glaciers grew, coalesced, 
and extended out upon the low grounds or into the sea according to 
situation. Such as reached the sea detached icebergs from their 
tronts, and these drifting hither and thither in the random fashion 
so characteristic of ice floating in a tideway, would scatter their 
loads of boulders in a very erratic and irregular fashion over the sea 
floor. A further stage of refrigeration would bring about further 
confluences of the ice streams, and such as debouched into such 
* Man and the Glacial Period (Internat. Scient. Series) pp. 137-181, and 
Geol. Mag. Nov., 1892, p. 491. 
