160 
Scaphopoda and Gasteropoda) which practically represent 
the whole collection, only a very small number of Vertebrates and 
Polyzoa forming the remaining part. . 
So far, 131 species have been identified (37 of Palecypoda, 
4 of Scaphopopa, 90 of Gasteropoda). This number does not in- 
clude nearly all the species, for I have seen in the stony material 
various impressions which show that many other species exist, though 
the impressions are not sufficiently clear to enable me to deter- 
mine them. 
The fossils were determined for Mr. Bateson in a preliminary 
way by T. Roberts and H. Keeping,') who considered them to be 
„about the age of the London Clay and of the Bracklesham Beds“, 
but most of their identifications 1 am unable to accept. Mr. Bateson 
in his paper does not give any detailed lithological description of 
the beds from which the fossils originate, but he very kindly sup- 
plied me with his manuscript notes made on the spot. From these 
notes, and from -the fairly large quantity of material brought toge- 
ther with the fossils, one can see that the two horizons as described 
by Bogachev and others are represented in all localities except 
Togus-Ken and Termenbes, where the upper horizon has most pro- 
bably been swept away by denudation. The total thickness exposed 
seems to be 450—500 feet. 
The relation of the faunas in the two horizons. 
We have seen that all previous writers are of the opinion that 
so far as the age of the faunas in ihe two horizons is considered, 
there is no difference whatever. Bogachev thinks that certain differences 
exist, but they are merely facial. Nevertheless he says that the lowest 
part of the series may be of the Uppermost Eocene age, while the rest 
is of the Lower Oligocene age. As can be seen from the accompa- 
nying table, only about twenty out of sixty seven species of the 
lower horizon and seventy three species of the upper horizon are 
common to both, ie., less than one third of the total number of 
species in either horizon. It can also be observed that the number 
of species identical or: more or les closely allied to those of the 
L. Oligocene of W. Europe is somewhat larger in the upper horizon. 
On the other hand if we compare the Jists of the different species 
in the two horizons, we shall notice that although different, they 
show very much the same character regarding their assamblage, 
and similar to that of the species common to both horizons, viz., 
that they are composed of both Eocene and Lower Oligocene spe- 
cies of Western Europe, or of those closely allied to them. Also, 
so far as we can judge by the species represented, we cannot con; , 
sider them as belonging to two distinct and independent stages. 
This is supported by the stratigraphical data given by the previous 
writers, who pointed out that no interruption in sedimentation can 
be noticed in the succession of beds. The thickness of the complex, 
however is considerable (450—500 feet exposed) and a relatively long 
time must have elapsed between the deposition of the lowest and 
the uppermost portion of it. All this taken together seems to show 
1) Phil. Trans. (1889) p. *897. 
