THE ICEFLOE HYPOTHESIS EXAMINED. 



541 



counting for the existence of ice in such latitudes, except by referring to the great vi- 

 cissitudes of European climate within the range of modern history. Yet how inade- 



blocks in the older strata with the higher temperature which, from other independent reason's also, was then 

 supposed to exist, and their presence in the modern sera with a diminished temperature. This accordance of 

 geological data with the result of an icefloe hypothesis is further borne out by modern analogies ; since, as far 

 as our inquiries go, no far transported large blocks have yet been found on the surface of equatorial regions. 



The preceding paragraphs in the text, including the first part of this note, were read to the Geological Society 

 just as they are printed ; and when I had no hope that the views they contain would have been so well sustained 

 as they have since been by modern analogies. (See next page.) I still adhere to my belief, that there is yet 

 no established case of far transported large bowlders in tropical regions ; but from fresh sources of informa- 

 tion I am led to suppose that the partial discovery of bowlders in such tracts, so far from weakening the icefloe 

 hypothesis, would almost support it by evidence drawn from existing causes. 



In 1 83 6, Captain Octavius V. Harcourt, R.N., returning in the North Star from South America, met with a vast 

 number of icefloes in the Pacific, in latitude 50°. Some of them were not less in size than two miles square 

 and 250 to 300 feet above the water. It is remarkable that this phenomenon occurred from 85° west longi- 

 tude, at a considerable distance from any land, to the meridian of Cape Pillar; while the immediate coasts of 

 Chiloe and Cape Horn offered no trace of them. The winter was comparatively mild, which might indeed 

 account for the liberation of such large masses of ice from the South Pole, and their being wafted into seas 

 usually quite free from them. The number and size of these icefloes were truly astonishing (two of them as 

 seen for a distance of three to four miles are represented in the wood-cut below), and Captain Harcourt had 

 the greatest difficulty in so steering, during the long winter moonless nights of 18 hours, as to avoid shipwreck. 

 Their course seemed to be from south-east to north-west, and they were met with through five degrees of latitude 

 (50° to 55°), which would be the exact position of England if transferred to the other hemisphere. Their occur- 

 rence was accompanied by sudden changes of wind and violent tempests. (Abridged from a letter of Captain 

 Harcourt to myself.) 



In the 7th Volume of the Journal of the Royal Geographical Society icefloes are mentioned by Mr. Bennett 

 (p. 212.) in latitude 47° south, and they have even been met with recently as high as 35° south latitude, the 

 parallel of Bengal in our hemisphere. 



The multitude of these icefloes sailing together for such a great distance from the source of their origin 

 before they are dissolved, not only teaches us, that any stones of the polar region which they might be trans- 

 porting, must now form part of submarine deposits, even in intertropical regions, but also explains how a vast 

 number of such stones might be collocated in one tract very remote from the parent rock, as in the south of 

 Staffordshire, p. 536 (ante). See Lyell's excellent illustration of this point, Principles of Geology, vol. iv. p. 267. 

 According to this author the mass of ice below the level of the water in floating islands is seven or eight times 

 greater than that above, and hence the islands here represented must have had a total altitude of from 2000 to 

 2500 feet! (See Scoresby's Voyage, p. 233.) 



109, 



Icefloes in the Pacific, from a drawing by Captain Octavius V. Harcourt, R.N. 



3 y 



