POLAR ICE NOT DUE TO ELEVATION. 73 



observed which could be regarded as bearing upon the 

 mode of original formation of the ice-mass, was an 

 occasional local thinning-out of some of the layers 

 and thickening of others — just such an appearance 

 as might be expected to result from the occasional 

 drifting of large beds of snow before they have time 

 to become consolidated." 



There cannot, I think, be the shadow of a doubt 

 that these thin horizontal bands of clear blue ice, with 

 their less dense and white intervening beds, are the 

 original structure of the bergs. And it is evident 

 that, if the ice had crossed mountain-ridges, valleys, 

 or other obstructions in the course of its journey from 

 the interior, these beds could not have avoided being 

 crushed, fractured, broken up, and mixed together. 

 Had this happened, it would have been physically 

 impossible that they could ever have been restored 

 to their old positions. Ice is, no doubt, plastic, and 

 pressure, along with motion, might perhaps induce 

 fresh lines of stratification ; but neither motion nor 

 pressure could have selected broken blue bands from 

 among the white and placed them in their old 

 positions. 



Why the icebergs from Greenland are not of the 

 tabular form, and stratified like those of the Antarctic 

 regions, is doubtless owing to the fact that the 

 Greenland ice is discharged through narrow fjords, 

 which completely destroy the original horizontal 

 stratifications. 



Let us now see the consequence to which the fore- 

 going considerations all lead. The tabular form and 

 flat-topped character of the icebergs, with their per- 

 fectly horizontal bedding, show that they have been 

 formed on a flat and even surface. They show also 

 that this flat surface is not a mere local condition, but 



