Phosphatic Deposit at Potton, in Bedfordshire. — 121 
call this fossil by a name which he knows to be the wrong one? 
On referring to Prof. Morris’s catalogue, I find that O. macro- 
ptera occurs in the Gault of Oxfordshire, in the Lower Greensand 
of Atherfield, and in the Greensand of Farringdon, where I 
found specimens during a recent visit. Mr. Seeley next states 
that he has seen no such shells as Exogyra conica &c., adding, 
“though I have long had other species of those genera in the 
Woodwardian Museum.” He ought to have given a list of the 
specimens, which I presume, from his statement, have been 
presented by him to the University Collection. 
X. With regard to this paragraph I can only say that, in my 
paper read before the British Association, I distinctly mentioned 
that fishes from the Kimmeridge Clay at Ely, specifically iden- 
tical with those from Potton, were exhibited in the Woodwardian 
Museum, and that I think the rolled condition of the Potton 
specimens is a sufficient “reason for thinking them other than 
tenants of the sea of the time.” I must confess that I am at a 
loss to understand the purpose of Mr. Seeley’s reference to the 
existence of named specimens of these fishes in the University 
Museum, unless he considers that no one has a right to consult 
a public museum without acknowledging each occasion on which 
he may have derived information from it. As regards the spe- 
cimens referred to in my paper, I had many of them in my 
possession and had determined them before any fossils from 
Potton were exhibited or, so far as I know, contained in the 
Woodwardian Museum. 
XI. I will not be behind Mr. Seeley in confessing what I dare 
not call the on/y mistake in my paper. There occur in this bed 
rolled fragments of a rock. composed almost entirely of shells ; 
the specimens found were very much decomposed, and presented 
precisely the aspect of fragments of the Cyrena-bed. Since 
_ then, more boulders of this rock have been found, in a better 
_ state of preservation. On breaking these, I also have found 
specimens of Cardium ; therefore I will admit that the specimens 
I mentioned in my paper probably contain the same shells. 
But I think that there is sufficient evidence of the denudation 
of the Wealden in the occurrence of the rolled bones of Lguano- 
don &c., and in the rolled fruits and wood. The wood exists 
in two different states of mineralization, as | remarked in my 
paper. Mr, Seeley states that he has shown in his paper “ that 
the material of the deposit came from the east.” I suppose he 
refers to one of his unpublished papers. 
XII. The species described by me as Sphera Sedgwickit, if 
not a Sphera, is probably the type of a new genus; if, however, 
it should hereafter be proved to be a Cyprina, I have no doubt 
that it will be found to differ considerably from C. angulata, Sow., 
