86 LIVERPOOL BIOLOGICAL SOCIETY. 
about ten yards §.S.W. of the house, where they bear 
8. 25° W.*; below the house, at a point also marked on 
the sketch map, other stris occur bearing S. 20° W., and 
at one or two other places on the dip slope of the island 
I found strie by removing the turf on the north slopes of 
humps of limestone. The strize agreed with the general 
direction of those in the district, which is given by 
Strahant as W.S.W., and still more closely with the 
average in Anglesey, which Ramsay recordst as 30° to 40° 
W. of S. The striz on Puffin are always very faint, 
but we must remember that they would soon become 
obliterated on exposed surfaces of this soluble limestone, 
and that where strize have been observed on this formation 
elsewhere, it has usually been on the more durable 
interstratified grit bands. The approximate parallelism, 
however, of those on the island clearly indicates their 
glacial origin. 
Surface configuration, which in many places affords 
reliable evidence of past glaciation, is here of doubtful 
service, as, though the limestone massifs of Puffin Island 
and the two Ormes Heads are, as Professor Ramsay puts 
it, ‘ strikingly mouwtonnée,”’ it would not be safe to attach 
much weight to this argument. 
As soon as we leave the record of observed facts for 
the discussion of their meaning we enter a field much 
frequented by geological Jingoes, as the form of ice agent 
that has been here at work has always been hotly con- 
tested. The theory that can lay the most valid claim to the 
palm of orthodoxy is that enunciated by Sir A. Ramsay, 
in the second edition of his ‘‘ Geology of North Wales.” 
According to this teacher, great glaciers took their rise in 
* The bearings given are magnetic. 
t+ Quar. Jour. Geol. Soc., vol. xlii., p. 381, 
+ Geology of North Wales, 2nd edit., p. 270. 
