British Association Reports. 517 
IV. Notice oF THE OccURRENCE OF CERTAIN Fosstzr SHELIS IN THE SEA-BED 
ADJOINING THE CHANNEL Istanps. By J. Gwyn Jerrreys, F.R.S. 
TE the course of his dredging explorations this year among the 
Channel Isles, Mr. Jeffreys found shells of species, some of 
which are extinct, and one is not known to inhabit at present 
the North Atlantic. They were taken, with living mollusca, at 
depths varying from 12 to 20 fathoms, and in different parts of the 
sea-bed. ‘The specimens in question had the same appearance as 
dead shells of recent species; one of them was in a most perfect 
state of preservation, and evidently had not been rolled or trans- 
ported to any distance from its original place of habitation. 
They consisted of Potamides tricarinatus, Lam. and P. einctus, 
Lam. (both Eocene fossils), a species of Lerebratula (or Terebra- 
tulina), which Mr. Davidson referred with doubt to J’. syuamulosa. 
of Baudon (from the Calcaire Grossier), and Aotalia (Discorbina) 
Trochidiformis of Lamarck, also an Eocene fossil, but larger than 
specimens from the Bracklesham beds. No Tertiary deposit has 
been noticed in any part of the Channel Isles; but the discovery of 
the above-mentioned fossils in the adjoining sea-bed, occupying an 
intermediate position, would seem to connect this district with 
Hampshire and Normandy, and to show the great extent of the 
Eocene basin or area which formerly existed. Another species 
obtained by the same dredgings, near Jersey, was Cerithium vul- 
gatum, Bruguiére. Several specimens were found, one in a tolerably 
fresh condition. ‘This species inhabits the Mediterranean and Adri- 
atic, throughout many parts of which it is most abundant. It does 
not appear that living specimens have ever been found elsewhere, 
although Lamarck gave the North Atlantic as a locality. M. Cail- 
liaud of Nantes included C. vulgatum in his list of mollusea from 
the Département of the Loire-Inférieure, having frequently met 
with shells thrown up on the beach; and Professor Sars recorded 
the discovery of a specimen inside a cod-fish caught off Bergen. 
Mr. Jeffreys believed that C. vulgatum, which usually inhabits large 
estuaries and salt marshes, once lived in such situations between 
Jersey and the mouth of the Loire, and that this tract has since 
been submerged, and consequently become unsuitable for the con- 
tinued habitation of the Cerithium. ‘The presence of submarine 
peat near the Channel Isles and in the bay of Mont St. Michel, tends 
to confirm the supposition, although it is by no means certain that 
the submergence has occurred within the historical period, as sug- 
gested by the Abbé Manet, Mr. Peacock, and others. Fossil shells 
procured by Mr. Jeffreys in his Shetland dredgings were of Arctic 
and high northern species; those now obtained were tropical and 
southern. 
V. On tHE BritisH Spectres oF THE GENUS CEPHALASPIS, AND ON THE ScoTcH 
Preraspis. By E. Ray Lanxssrsr, Scholar of Downing College, Cambridge. 
vee author of this paper stated that he had acquired a very large 
amount of evidence with regard to these remarkable fishes, by 
the kindness of various geological friends, in particular, Mr. Powrie, 
