378 Geology of 



form such conspicuous cliffs along the "West Coast. The reasons for 

 ■doing so are the existence of enormous erratic blocks standing above 

 the sea in front of the moraines, and the breaking of the surf in many 

 localities far outside the coastline, so as to show that the morainic 

 accumulations continue outwards for a considerable distance below the 

 level of the sea. Examining in that district the intervening spaces 

 between the ancient moraines, we find that they consist generally of 

 level swampy or marshy ground. This at once suggests that when the 

 glaciers advanced far beyond the foot of the ranges they must have 

 extended either upon low level ground, or actually must have entered 

 the sea for a long distance ; the latter assumption gains in strength by 

 observing that in front of the swampy ground, between the morainic 

 accumulations, a shingle or sandspit has evidently been thrown across, 

 the material having travelled, as it does at the present time, in a 

 northward direction. Thus the sea appears to have once entered far 

 between the glaciers and the morainic deposits flanking them, being cut 

 off in course of time in the same manner as Lake Eilesmere during 

 its greatest extension was separated from the sea by similar deposits of 

 shingle and sand, both travelling in a north and south direction towards 

 "what is now Banks' Peninsula. The lagoons thus formed between the 

 ancient glaciers or their deposits were in course of time filled either 

 by decaying vegetation and silt, or near the slopes of the Alps by 

 the deposits of water-courses descending from the secondary ridges. 

 When standing on some prominent elevation amongst -the West Coast 

 moraines, and looking over these low swampy forest covered plains, 

 dotted over in many localities with numerous ponds, it is easy to 

 restore the picture as it must have appeared during the Great Glacier 

 period. 



Let us now examine if we have at present in the Arctic or even the 

 more temperate regions, any analagous glaciers of the breadth of 

 several miles, advancing 12 to 15 miles into the sea, till their frontal 

 portion is washed away. I have already alluded to Darwin's researches 

 in South America, showing that in latitudes corresponding to the 

 northern end of Stewart's Island or to the latitude of Central France, 

 glaciers of considerable size enter into the sea, their terminal face 

 being ultimately washed away and carried along as huge icebergs ; 

 and as the mountains where their neves are situated are not nearly so 

 high as the Southern Alps, similar conditions to those prevailing in 

 New Zealand during the Great Glacier period must still reign in these 

 latitudes. 



