Cause of the Glacial Period 
CORROBORATIVE VIEWS OF SOME AUTHORITIES 
Colonel H. W. Feirpen, F.G.S., writes to the author, December 13th, 1896 :— 
I am inclined to think that there is much force in your view that the so-called Glacial epoch was due ina great 
measure to some deflection of the warm current from the Polar basin. 
If Professor Spencer is correct the elimination of the Gulf of Mexico would deprive the Northern Atlantic of its 
chief heating apparatus, and might induce glacial conditions over Scandinavia. If a system of glaciation sets in anywhere, 
where the precipitation exceeds the melting forces, there is no saying where it may end, given sufficient lapse of time. 
There is, however, another side of the proposition, about which I should like your opinion. 
Undoubtedly the glaciation of the vast island-continent of Greenland, 1200 miles in extent, north and south, is 
due to the refrigerating influences of the great Polar drift of cold water sweeping down its east side, swirling round Cape 
Farewell, and running up to Holstenborg on the west side; whilst the icy current coming down Smith Sound 
plays a similar part on the west side. 
"Now if we could deflect this Polar current, so that it came down the Baltic, as it probably did, and along the west 
side of Norway, would not Scandinavia be as glaciated as Greenland, and England, Scotland, and Ireland, and the 
Faeroes, much as Spitsbergen is to-day ? 
Again, is there any proof that the glaciation of North America was coincident with the Glacial epoch of Europe? 
Most travellers in those regions have. pointed to the proofs of remarkable rapid elevation in recent times of the 
islands of the American Archipelago and of Grinnell Land, where recent shell-beds stand at an elevation of 1000 feet. 
If we could again sink the American Archipelago 1000 feet, the fender or buttress which keeps out the 
Palaeocrystic ice would be removed, and that ice would pile up on the shore of the continent of America, much farther 
south than now, and probably glaciate it. 
Here Colonel Feilden asks my opinion on the question, whether by the deflection of the North Polar 
current down the Baltic and the west coast of Norway, Scandinavia would be as glaciated as Greenland ? 
and he points out that this might take place by the submergence of the islands of the American 
Archipelago which have recently been upraised to the extent of 1000 feet, as shown by beds of shells. 
The passage of a Polar current down the Baltic would require the submergence of Lapland to the 
extent of over s00 feet, a state of things which in all probability formerly existed ; and the passage of a 
north current would doubtless have the effect described. But it is to be observed that the greater part of 
Greenland lies farther north by 10° than that of Scandinavia, the effect of which would be to cause the 
climate of the latter to be less rigorous under any circumstances; and this result would be accentuated 
by the prevalent wind-currents. 
Colonel Feilden also inquires whether there is any proof that the glaciation of North America was 
coincident with the Glacial epoch of Europe? 
My reply is, that although there may be no proof, the probabilities are in favour of the view, 
as the uplift of the land and ocean-bed seem to correspond on both sides of the Atlantic, as I have 
endeavoured to show. But it is otherwise with the western side of the American Continent, where 
reciprocal (not simultaneous) conditions appear to have prevailed, as Professor Spencer has recently 
shown, in his paper on the “ Oceanic Connection of the Gulf of Mexico with the Pacific” (Bu//. Geol. 
Soc. Amer. vol. ix., 1897). 
The late Professor T. Rupert Jones, F.R.S., writes :— 
Fanuary 15th, 1898. 
I have read Professor Hull’s paper read before the Victoria Institute, with much pleasure. He seems to establish 
the following facts and conclusions. 
If we trace the 100-fathom line around the British Islands, as indicated on the Admiralty Charts, we notice that 
opposite to the river-mouths opening out on the coasts there are corresponding indentations. So also off the North- 
East American and other coasts the deep-sea contour lines run parallel with the bays and river-mouths ; and moreover 
the valleys of the land are continued by definite lines of relative depths (shown by soundings) down the great 
irregular slopes of the sea bottom. These lines of valleys and gorges cross plateau after plateau on the ocean floor, 
and notch their precipitous edges with successive gaps. These valleys are traced downwards and outwards for more 
than 200 miles, and even to a depth of two or more miles below the present surface of the water, before they are lost 
on the abyssal floor of the ocean. 
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