28 , president's address. 



several districts. The present temperature of West-Central Scotland 

 may be taken as 47°; its surface as averaging about 2,500 feet, rising 

 occasionally to nearly 4,000 feet above sea-level. In the western part 

 of the Southern Uplands the temperature is a degree higher, and the 

 average for altitude at most not above 1,500 feet. In the Lake Dis- 

 trict and the Northern Pennines the temperature is increased by another 

 degree, and the heights are, for the one 1,800 feet with a maximum of 

 3,162 feet, for the other 1,200 feet and 2,892 feet. In North Wales 

 the temperature is 50°, the average height perhaps 2,000 feet, and the 

 culminating point 3,571 feet. For the purpose of comparing the ice- 

 producing powers of these districts we may bring them to one tempera- 

 ture by adding 300 feet to the height for each degree below that of the 

 Welsh region. This would raise the average elevation of Central and 

 Southern Scotland to 3,400 feet and 2,100 feet respectively ; for the Lake 

 District and Northern Pennines to 2,100 feet and 1,500 feet. We may 

 picture to ourselves what this would mean, if the snow-line were at the 

 sea-level in North Wales, by imagining 8,000 feet added to its height 

 and comparing it with the Alps. North Wales would then resemble a 

 part of that chain which had an average height of about 10,000 feet 

 above sea-level, and culminated in a peak of 11,571 feet; the Lake Dis- 

 trict would hardly differ from it ; the Northern Pennines would be like a 

 range of about 9,000 feet, its highest peak being 11,192 feet. Southern 

 Scotland would be much the same in average height as the first and 

 second, and would rise, though rarely, to above 11,000 feet; the average 

 in Central Scotland would be about 11,400 feet, and the maximum about 

 13,000 feet. Thus, North Wales, the Lake District, and the Southern 

 Uplands would differ little in ice-productive power; while Central 

 Scotland would distinctly exceed them, but not more than the group 

 around the Finsteraarhorn does that giving birth to the Ehone glacier. 

 In one respect, however, all these districts would differ from the Alps — 

 that, at 8,000 feet, the surface, instead of being furrowed with valleys, 

 small and great, would be a gently shelving plateau, which would favour 

 the formation of piedmont glaciers. Still, unless we assume the present 

 distribution of rainfall to be completely altered (for which I do not know 

 any reason), the relative magnitudes of the ice coming from these centres 

 (whether separate glaciers or confluent sheets) could differ but little. 

 Scottish ice would not appreciably ' shoulder inland ' that from the Lake 

 District, nor would the Welsh ice be imprisoned within its own valleys. 

 During the last few years, however, the lake-hypothesis of Carvill 

 Lewis has been revived under a rather different form by some English 

 advocates of land-ice. For instance, the former presence of ice- 

 dammed lakes is supposed to be indicated in the upper parts of the 

 Cleveland Hills by certain overflow channels. I may be allowed to 



