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explorers are apt to "be misled in the way Wilkes was. The 

 barrier is so unlike anything that occurs in the Arctic regions 

 and is so remarkable a feature in the Antarctic, that a few 

 minutes may be devoted to explaining its formation. The 

 late Sir Wyvill Thompson, in a lecture delivered by him at 

 Glasgow, gives a very interesting account of the peculiarities 

 of Antarctic ice, and to him I am largely indebted for what 

 follows : — 



Some idea of the formation of the barrier may be gathered 

 from an examination of the icebergs found floating north- 

 wards, often as low as 42deg., in the track of vessels making 

 the Australian voyage. All observers agree in describing 

 these bergs as being fundamentally of a tabular form, com- 

 posed of layers cf ice in regular strata of varying degrees of 

 density. It is true that as these bergs reach warmer waters 

 their original forms become obscure, and they melt into all 

 sorts of irregular shapes, but they always retain their original 

 lines of stratification. They are entirely different to the 

 Arctic bergs, which are always of irregular or fantastic shapes, 

 and entirely devoid of stratification ; this difference is to be 

 ascribed to the different circumstances attending their 

 formation and not to difference of weathering. As a general 

 rule, the Arctic Coast line, except in winter, is bare or only 

 fringed with broken ice. Deep indentations resembling 

 those on the Norwegian Coast, are numerous, and invariably, 

 at the head of these indentations, glaciers push their 

 way into the sea. It is these glaciers or ice rivers that 

 furnish the Arctic bergs. The general ice sheet is compara- 

 tively thin ; on the coast of Greenland, as far north as 

 Peterman Inlet, it is not more than 40 feet thick. The 

 Antarctic bergs are masses broken off from the great barrier ; 

 they are often of immense size, several have been noticed over 

 four miles long. The stratification is due to the fact that 

 they are formed by successive layers of snow falling upon flat 

 land. The water in front of the land being shallow, and the 

 land itself presenting but a slight slope, the ice moves slowly 

 forward, pushing its way into the sea until it reaches water 

 so deep that the lower stratum of ice no longer rests upon 

 the bottom ; part of the mass then breaks off and floats away 

 before the prevailing winds. "Whilst this is going on the 

 surface is constantly receiving fresh deposits of snow ; these 

 partially melt, and then freeze again into ice. When the 

 bergs first float away their lines of stratification are parallel 

 to the surface of the sea ; as their bases melt their centres of 

 gravity becoming changed, they roll over, exposing fresh 

 surfaces, and tilting up the strata at various angles. Caves 

 are worn into the perishing ice, and the superincumbent strata 

 often bend, exhibiting those foldings and contortions we are 



