43 
Eastern and Western seas, and of seas North and South of 
the British Isles. 
The present list was specially remarkable for including 
Cytherea chione, Cardium msticum, Cardium aculeatum (?), 
and Area lactea ; all of them shells reaching their highest 
northern range in the extreme south or west of England 
and Ireland, a circumstance believed to be new to the history 
of the so-called “ Drift.” t 
The Macclesfield list rendered probable the deposit of those 
beds from the westward, after the period had commenced 
during which the physical conditions of the Western Sea have 
differed as they now do from those of the Eastern. 
A depression of 600 feet would leave only a few islands 
where Ireland is, would allow of a great extension of the tidal 
current now narrowed in St. George’s Channel, and would 
probably carry the warmer influences which are now checked 
on the West of Ireland to the shores of the Derbyshire hills. 
Are there any traces of the sea bottom or shores on which 
the shells of the drift seas lived ? 
Mr. Darbishire further mentioned his identification in a 
bed of gravel discovered by Mr. Prestwich, F.G.S., at about 
1,200 feet above the sea, on the east side of Macclesfield, of 
nine species of shells, including Cytherea chione. 
Mr. Binney, F.G.S., remarked on the extent of the list, 
the great distance eastward from the present shores of the 
deposit, the elevation of Mr. Prestwich’s patch, and the 
peculiarly temperate aspect of the group of shells. This drift 
could not be called “ arctic.” He also referred to the diffi- 
culty of recognising distinct “ upper” and “ lower” boulder 
