280 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
to the east and that to the west of the Isle of Man (see 
fig. 8). The eastern part is the wide shallow-water 
area (discussed in the main by Mr. Johnstone and 
Dr. Bassett in their articles on the temperatures and 
salinities of the Irish Sea in this report), where the daily 
rush of the tides mixes up the waters to such an extent 
that any distinctive characters indicative of origin are 
obliterated. The water to the west of the Isle of Man, on 
the other hand, is so much deeper, and that deep water is 
of such extent, that if the floor of the Irish Sea were raised 
so as to connect the Isle of Man with Lancashire, there 
would still be a wide western channel between Port Erin 
and Ireland not very different in extent from that seen at 
present. Moreover, this deep-water area west and south 
of the Isle of Man (see fig. 8) is precisely the region 
marked on the Admiralty Charts as having no perceptible 
tidal stream. For these reasons we consider it a priori 
probable that, for example, the water of.over 50 fathoms 
in depth may show stratification in both its physical and 
its biological characters which will indicate the nature 
and origin of the layers. Mr. Johnstone tells us that he 
got no indication of such layers in the deep water at a 
poit further north between the Mull of Galloway and 
Ireland; but on the other hand, our mid-channel 
Stations A and B, at 64 and 74 fathoms respectively, and 
in the comparatively still area referred to, and in the 
observations we took at these stations last summer, 
Mr. Drew considers we got evidence of stratification. It 
is evident that the whole matter requires further investi- 
gation; but we must insist in the meantime on the obvious 
difference in character between the wide, shallow, sandy 
eastern part of the Irish Sea and the deep channel lying to 
the west of the Isle of Man. Observations made in the 
one area, or conclusions drawn from them, must not be 
regarded as applicable to the whole of the Irish Sea. © 
