AQ On Arctic Interglacial Periods. 
Spitzbergen, having been probably routed out by the ice- 
masses constantly driven by the ocean-currents along the 
coasts.” * 
This testimony is the more valuable as it is given by an 
experienced geologist so much opposed to the theory ef inter- 
glacial periods. A more special and thorough search of 
those beds might probably reveal further indications of inter- 
glacial age. 
Was Greenland free from Ice during any of the Interglacial 
Periods ?—There is nothing whatever improbable in the sup- 
position that during some of the earlier interglacial periods, 
when the eccentricity was about a maximum, the ice might 
have completely disappeared from Greenland, and the country 
become covered with vegetation. 
Mr. Wallace thinks that the existence at present of an 
ice-sheet on Greenland is to be explained only by the fact 
that cold currents from the polar area flow down both sides 
of that continent. He farilien thinks that could these two 
Arctic currents be diverted from Greenland, “that country 
would become free from ice, and lige. even be completely 
forest-clad and habitable.”’ 7 
I am inclined to agree with Mr. Wallace in thinking that 
the withdrawal of the two cold currents in question would 
effectually remove the ice. We know that Greenland is at 
present buried under ice, as has been shown on former occa- 
sions, simply because there happens to be about two inches 
more of ice annually formed than is actually melted. It 
certainly would not require any very great change in the 
present physical and climatic conditions of things to melt 
two additional inches per annum. If this were done the 
ice would ultimately disappear. A simple decrease in the 
volume of the two currents might possibly bring about such 
a result. A cause more effectual would, however, be an 
increase in the temperature and volume of the Arctic branch 
of the Gulf-stream. 
Norr.—This will probably be my last paper on questions 
relating to geological climate. There are many points I 
should have wished to consider more fully, but advancing 
years and declining health have rendered it necessary for me 
to abandon the subject altogether in order to be able to finish 
some work, in a wholly different field of inquiry, which has 
been laid aside for upwards of a quarter of a century. 
* ‘Qn former Climate of Polar senna? Geol. Mag. Nov. 1875, p. 531. 
See also “Geology of bt Geol. Mag. 1876, p. 267. 
+ ‘Island Life,’ p. 149. 
