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VOL. XIV. (1) FOREST BED—PALHONTOLOGY 39 
Valvata piscinalis (Mill.) Common. On the continent 
this form is first known from the Lower Pliocene(Coxgerza- 
beds) at Moosbrun, Vienna, and St. Leonhards in West 
Slavonia, whilst in this country it has been found in the 
Icenian of Bramerton. At the present day it ranges from 
Europe through Siberia and Turkestan to Tibet and 
Kashmir. 
Valvata cristata, Mill. Five examples. This species 
is confined to Europe, though it is an ancient form, being 
known from the Icenian of Bramerton. On the Con- 
tinent it is known from the Lower Pleistocene of Mosbach, 
a deposit which is generally considered to be of the same 
age as the Cromerian of this country. 
Spherium corneum (Linn.) Three examples. This form 
is also an ancient species occurring in the Icenian, though 
on the Continent it is not known to occur in any earlier 
bed than the Middle Pleistocene of Potsdam. It is 
confined to Europe. 
Pisidium amnicum (Mill) Common. An _ Icenian 
species ; it is also known from the Amstelian of Holland, 
and from the Upper Pliocene of Bligny, near Dijon, 
France. It is abundant in the Pleistocene of the Thames 
Valley and in later beds. It occurs at the present day 
throughout Europe and Siberia. 
Pisidium pusillum (Gmel.) Common. Like the pre- 
ceding, it is an Icenian species, but on the Continent its 
earliest appearance is the Middle Pleistocene of Cannstadt. 
It is circumpolar in its distribution. 
Pisidium fontinale (Drap.) Common. The geological 
history of this species is similar to the preceding, and it 
has an identical range at the present day. 
CONCLUSION. 
There can be little doubt that the fauna detailed above, 
as well as that mentioned in the following appendices, 
D 
