88 Geological Society of London. 
below the coal. ‘The anomaly, therefore, in the supposed position 
of these fossils was so great, that between the ordinary geological 
site of such remains, and that in which they were here inferred to 
present themselves, there would be interposed, if the series were 
complete, the whole of the old red sandstone, and at least the two 
upper formations of the Silurian system. When this point was con- 
sidered, I expressed to the Society my opinion in common with 
Mr. Murchison, as to the insufficiency of the proofs relied on by our 
Foreign Secretary, and we feel that we had a right to call for more 
conclusive evidence. ‘The simple fact of shales having been found 
charged with true coal plants, raised so strong a presumption in favor 
of their belonging to the regular carboniferous series, that the bur- 
then of proof rested with him who wished to assign to them either 
a higher or lower position. Our scepticism was regarded by Mr. 
Greenough as implying too marked a bias for a preconceived theory, 
and this he afterwards hinted in his anniversary address.* I may 
affirm, however, that in the first place it implied on my part no dis- 
trust of Mr. De la Beche’s skill or experience in geological survey- 
ing, and that had Prof. Sedgwick and Mr. Murchison advanced a 
similar opinion on analogous proofs, I should equally have withheld 
my assent. Suppose, for example, they had announced to us that 
they had found fossil fruits and leaves identical with those of Shep- 
pey in strata of the age of the white chalk with flints. I should 
have demanded from them, in corroboration, the most clear, une- 
quivocal, and overwhelming evidence. ‘If it were a region of dis- 
turbed and vertical strata, I should expect them first to have resort- 
ed in vain to every hypothesis of inverted stratification with a view 
of explaining away such an exception to the general rule. 
I might perhaps be told that we are unacquainted with the flora 
of the upper cretaceous period, and I admit that we are as ignorant 
of it as of that which belonged to the transition period, but when we 
consider the contrast of the shells and other fossils of the chalk and 
London clay, we naturally anticipate that if plants are ever found 
of the precise age of our chalk with flints, they will not prove to be 
of the same species as those of the Sheppey clay. There is a like 
presumption from analogy against the conclusion that the same vege- — 
tation continued to flourish on the earth from the period of the lower 
greywacke to that of the coal, because we know that in the course 
* Proceedings Geol. Soc., vol. ii. p. 164. 
