42 Scientific Proceedings, Royal Dublin Society. 
V.—SOME REMARKS ON INTER-GLACIAL EPOCHS, IN RE- 
FERENCE TO FAUNA AND FLORA EXISTING AT THE 
PRESENT DAY IN THE NORTHERN HEMISPHERE, 
BETWEEN THE PARALLELS OF 81° AND 83° N., By 
H. W. FEILDEN, F.e.s. 
[Read May 20, 1878. ] 
In the brief paper that I have the honour of submitting to your 
notice, it is my desire to draw your attention to the theory of 
intercalation of series of warmer climates during what is called 
the Glacial Epoch. 
Tnaccordance with the opinions of Professor Oswald Heerand the 
late Sir Charles Lyell, the existence of Inter-Glacial Periods has been 
indisputably evidenced by the Diirnten beds of Switzerland, and 
the Forest bed of our Norfolk coast ; and while Professor Heer 
considers that the Diirnten lignite beds represent the existence 
of a climate similar to that now existing in Switzerland, Lyell 
remarks that the Forest bed of Cromer presents a singular analogy 
to that of Diirnten, and that “both of them alike demonstrate that 
there were oscillations of temperature in the course of that long 
period of cold.”* 
Mr. James Geikie in his valuable work, “The Great Ice Age,” 
has likewise adopted the theory of the intercalation of warmer 
climates to account for the inter-glacial beds of Scotland. In fact, 
so many of our greatest modern authorities have given their ad- 
hesion to this theory, that it may almost be regarded as an accepted 
fact amongst modern geologists. That the so-called inter-glacial 
beds of Scotland and England were deposited between the com- 
mencement of the Glacial Epoch and its final withdrawal from 
Great Britain, is a well-established fact; but the question I am 
desirous of presenting to your consideration is, whether the so- 
called inter-glacial beds represent what Lyell terms “ oscillations 
of temperature,” or merely modifications of temperature due to 
* Lyell. Principles of Geology, vol. i. p. 196. Eleventh edition. 
