318 CLIMATIC CONDITIOKS OF THE GLACIAL EPOCH. 



Such being the facts with regard to the chmatic and other conditions in 

 hiirh southern latitudes, we seem to be justified in doubting whether the ice 

 fields of that region are not, as alread}^ suggested, more the result of the freez- 

 ing of the ocean surface than of the conversion into ice of snow which has 

 fixllen on the land. The peculiar forms of the Antarctic floating ice masses, not 

 resembling those seen in northern seas and which are known to be icebergs 

 originated from glaciers ; their mode of distribution, which appears to be — 

 to a considerable degree, at least — independent of the land ; the just doubts 

 as to whether the ocean does not occupy by far the larger portion of the sur- 

 face within the Arctic Circle ; the absence of an ice barrier at the base of 

 ranges of mountains over 10,000 feet in elevation in the highest southern 

 latitudes visited : these, and other facts which want of space makes it im- 

 possible here to indicate in detail, form the evidence in favor of the idea 

 that the Southern Polar -'ice-cap" — so far as such exists — is simply frozen 

 ocean surface, and therefore cannot be used as illustrative of the conditions 

 of a Glacial epoch on lamh where only such an epoch can be of importance to 

 the geologist. 



As already suggested,* the frozen surAxce of the ocean, in high northern 

 latitudes, does not seem to give rise to sheets of ice of great thickness, such 

 as those which occur in the Antarctic regions. The reason of this seems 

 to be, that the heat of the Northern Polar summer melts away from the 

 surface as much, or nearly as much, as is added during the winter. The 

 theory of Miihry with regard to these ice masses of the south is, that they 

 are formed by addition of frozen material from beneath. He thinks that 

 they are of great age, and that they are increasing in thickness. This idea of 

 their origin is supported by the evident marks of perfectly uniform horizontal 

 stratification of the ice reported by the different explorers of the Antarctic 

 region. 'These are of such a character that it does not seem possible that 

 they should be originated by glaciers on land. It is an interesting feet that 

 the " floebergs " of the Nares Expedition, which are masses of salt-water ice 

 of great size and peculiar appearance, and which were so called in order to 

 distinguish them from ordinary icebergs (born of glaciers), are described as 

 having precisely the same peculiar tabular form and horizontal stratification 

 which characterize the Antarctic barrier ice.f 



* See ante,, j). 292. 



t See Shores of Uie Polar Sea, a Narrative of the Arctic Expedition of 1875- 6, by Dr. Edward L. Moss, H. M. S. 

 " Alert." London, 1878. This is a folio volume illustrated by large chromolithographs. No. XII. of the series 

 shows the peculiar form and structure of the "floeberg." The writer has searched in vain among numerouii pho- 



