1 877.] The Great Ice Age and Origin of the “ Till.” 21 7 
Although so different from anything at present produced 
by the Alpine or Scandinavian glaciers, this great deposit is 
unquestionably of glacial origin. The evidences upon which 
this general conclusion rests are fully stated by Mr. Geikie, 
and may safely be accepted as incontrovertible. Whence, 
then, the great difference ? 
One of the suggestions to which I have already alluded as 
afforded by reading Mr. Geikie’s book was a hypothetical solu- 
tion of this difficulty, but the verification of this hypothesis 
demanded a re-visit to Norway. An opportunity for this 
was afforded in the summer of 1874, during which I travelled 
round the coast from Stavanger to the Arctic frontier of 
Russia, and through an interesting inland district. The 
observations there made, and strengthened by subsequent 
reflections, have so far confirmed my original specula- 
tive hypothesis that I now venture to state it briefly as 
follows : — 
That the period appropriately designated by Mr. Geikie as 
the “ Great Ice Age ” includes at least two distinct periods 
or epochs — the first of very great intensity or magnitude, 
during which the ArCtic regions of our globe were as com- 
pletely glaciated as the Antarctic now are, and the British 
islands and a large portion of Northern Europe were glaci- 
ated as completely, and nearly in the same manner, as 
Greenland is at the present time ; that long after this, and 
immediately preceding the present geological epoch, there 
was a minor glacial period, when only the now existing val- 
leys favourably shaped and situated for glacial accumulations 
were partially or wholly filled with ice. There may have 
been many intermediate fluctuations of climate and glacia- 
tion, and probably were such, but as these do not affect my 
present argument they need not be here considered. 
So far I agree with the general conclusions of Mr. Geikie 
as I understand them, and with the generally received 
hypotheses, but in what follows I have ventured to diverge 
materially. 
It appears to me that the existing Antarctic glaciers and 
some of the glaciers of Greenland are essentially different 
in their conformation from the present glaciers of the Alps, 
and those now occupying some of the fj elds and valleys of 
Norway ; and that the glaciers of the earlier or greater gla- 
cial epoch were similar to those now forming the Antarctic 
barrier, while the glaciers of the later or minor glacial 
epoch resembled those now existing in temperate climates, 
or were intermediate between these and the Antarctic 
glaciers. The nature of the difference which I suppose to 
