930 JOHN MILNE ON THE ACTION OF 



Passing by this extreme case, and considering the generality of 

 islands as exhibited in these three districts (but more especially 

 perhaps those of Finland) with regard to the way in which they are 

 acted on by ice, I divide them into the following three groups : — 



1. Rocks which at high water are hidden from view, but at low 



water appear as small islands. 



2. Those small islands which are always above sea-level, but yet 



are annually covered with ice, which is driven up their sides 

 and over their summits by outside pressure. 



3. Those islands whose summits are beyond the influence of ice. 



The tops of these are generally covered with trees and 

 vegetation, whilst others, which are usually not so high, have 

 only a black colour, probably due to a growth of lichen. 



Islands emerging from an ocean, as these appear to be doing, 

 must successively pass through the stages I have enumerated. 

 During the first two of these stages they are wholly within the 

 influence of coast-ice, as may be clearly seen from those islands on 

 the Finnish coast, which have not only been moulded, but are kept 

 of a whitish colour by the scouring they continually undergo. This 

 latter character is especially noticeable in the islands of the third 

 class, the upper parts of which have been raised so high that they 

 are now beyond the influence of the scouring agency ; these parts 

 are black with a growth of lichen, whilst those at a lower level, 

 which are annually invaded b}' the ice, are kept of a whitish colour. 

 New, between the dark upper parts of such islands as I have classed 

 in this last group and their lower parts, so far as I could see, there 

 is a continuity in contour between the undulations and curves along the 

 margin of the water {ivhich I know to have been produced by coast-ice) 

 and those ivhich lie at higher levels. From this it seems to me an 

 inevitable conclusion that the upper mouldings were produced in the 

 same way as those below, and have since been raised to their 

 present position. 



Should two or three, or, still better, a whole archipelago of these 

 islands slowly rise to unite and form a continuous land surface, I do 

 not think it would be unlike many parts of Finland. 



Turning from the islands to the adjoining mainland, it seems 

 natural to conclude that the actions which produced the features in 

 the one were identical with those producing the features in the 

 other. 



In these arguments it must be remembered that not only does 

 the action of coast-ice upon an oscillating area explain many phe- 

 nomena of ordinary occurrence, but it also readily explains some 

 phenomena, such as the appearance of erratics at levels higher than the 

 parent rock from which they were derived, which would be difficult 

 to account for by either the action of sheets of ice or of glaciers. 



Icebergs I have not considered, because, both from my own obser- 

 vations and more especially from the observations of those whose 

 labours lie amongst them, I believe them, as compared with all other 

 forms of ice, incomparable as transporters of material, and, from 



