384 NATURAL SCIENCE [December 
the widespread Irish animals as Dr Scharff claims by referring them 
to his ‘South-central’ group. 
I quite agree with Dr Scharff in rejecting the theory that the 
whole of our fauna is post-Glacial, since that theory would require 
us to regard the Arctic animals as the oldest, whereas the distribu- 
tional facts require us to consider the South-western section the 
oldest. But it seems to me that we are equally bound to consider 
the animals of the Northern fauna—restricted as they are to the 
hill regions and the west—-as more ancient than the widespread 
species which form the dominant element in our fauna to-day. I 
am quite prepared to believe that many of these widespread species 
inhabited the southern part of our area throughout Pleistocene times, 
but it seems unlikely that they extended their range far to the 
north or west until the glacial conditions had passed away. Dr 
Scharff apparently believes that, the glacial deposits being due to a 
marine submergence, sufficiently extensive land tracts must have 
been left to enable the whole fauna to survive. But even many 
geologists who reject the theory that the Boulder Clay is a ground 
moraine, consider that the polished and scratched rock-surfaces 
beneath that deposit are evidences of a former extension of land-ice. 
In the opening paragraphs of his paper, Dr Scharff makes the 
suggestive remark that the study of the fauna of a single island is 
the best starting-point for the study of a continental fauna. Hence 
he takes Ireland as the key to the greater problem of Europe. It 
seems likely that considerable light would be thrown on the special 
British problem by one of the smaller British islands, and I believe 
that in the Isle of Man we have evidence of a post-Glacial land- 
connection between Ireland and western England. Professor Carvill 
Lewis! and Mr Percy F. Kendall? found traces of glaciation up to 
the summit of the highest hills in the island, the former remarking 
that the whole shape of Snaefell is that of a ‘roche moutonnée.’ 
Whether we believe with these geologists that the ‘Irish Sea 
glacier’ passed over the summit of Snaefell, or prefer to consider 
the high-level drifts, boulders, and striated rock-surfaces as evidences 
of an ice-laden sea, it seems equally certain that the present in- 
habitants of Man must have reached that isle since the climax of 
the Glacial Period. 
Now the fauna of the Isle of Man resembles on the whole that 
of Ireland, western England, and Wales. Its cliffs form the most 
northern station for certain species of moths, such as Dianthoecia 
luteago var. barrettii, D. caesia and D. capsophila, some of which are 
scattered along the.western British and the eastern and southern 
Trish coasts as far as Land’s End and Dingle Bay. If the Isle 
of Man could not have supported any fauna during the height of 
1 «Glacial Geology of Great Britain and Ireland,” p . 857-9. ? Op. ctt., pp. 483-4. 
