1905-6.] Is BELIEF IN A GLACIAL PERIOD JUSTIFIED? 281 
Ocean, and cross the second traverse watershed, then after descending 
to the level of the Saskatchewan valley, again ascend the slope amounting 
to over four feet per mile, to the first traverse watershed and plateau 
of the lignite tertiary. Such an ice sheet moving throughout on broad 
plains of soft unconsolidated cretaceous and tertiary rocks would be 
expected to wash the surface with broad flutings parallel to its direction 
and to obliterate the transverse watersheds and valleys.” 
- Dr. Croll’s teaching differs from that of Agassiz, inasmuch as it 
involves the conclusion that there has been throughout geological time, 
an alternate glaciation of each hemisphere, ultimately caused by changes 
‘of eccentricity of the earth’s orbit directly engendered by the greater 
amount of warm water forced into each hemisphere by the alternate greater 
potency of the trade winds north and south of the Equator. With Dr. 
Croll’s allegation, that any material alteration of the direction of the Gulf 
Stream in the Atlantic and the Karo Siwo in the Pacific, would materially 
affect the climatic conditions, both on the European and American con- 
tinent I have no disposition to question, but when he claims that the Gulf 
Stream, which is largely fresh water, (and is as he admits five miles broad 
by 1,000 feet deep) could be permanently affected by the wind and not by 
the Amazon and Mississippi rivers, which gave it birth, I claim that we are 
at least entitled to the Scotch verdict of ‘‘not proven.’’ There is, however, 
one point where the doctrine of uniformity does not hold good between 
the two continents, namely that whilst in Europe the Pleistocene diluvials 
are largely marine, those of the interior and by far the larger portion of 
America are undoubtedly lacustrine. Agassiz also bears witness that the 
boulders of the American continent, are more rounded and that they show 
considerably less angular erratics than are to be found in the north of 
Europe. Thus we must admit that during the Pleistocene period there has 
been, not only a considerably larger fresh water lake area than at present 
exists, but that it had its outlet in Hudson’s Bay in North America, and 
that the Amazonian Lake in South America had its exit further south. 
Also that this phenomenon could have resulted from a gradual rising of the 
continent on the Atlantic Coast and a corresponding depression of the 
Pacific Coast, or in other words a reversion of the action which is now going 
on. Dr. Croll claims that the so-called glacial period of the Pleistocene 
epoch took place, by alternations of 10,000 to 12,000 years approximately 
between 240,000 and 800,000 years ago and that there was also a previous 
period of alternating glacial phenomena between 980,000 to 720,000 
years ago, having much greater severity, the alternations being the same. 
J. Geikie claims from discoveries made in the Kent Cave, that prior 
to the Pleistocene glaciation, the Paleolithic man lived and died, in the 
_ eaves of England and Northern Europe and that elephants, rhinoceroses, 
