REVIEWS—THE OLD GLACIERS OF SWITZERLAND, ETC. 53 
picture in addition the likeness of a northern sea, girt with protrud- 
ing glaciers from which drift off the floating icebergs with their freight 
of rock and stone. Thisrocky freight, as the icebergs melt in lower 
latitudes, is necessarily scattered over the hill-tops, the plains, and 
valleys of the deep sea-bottom. We must picture also, over broad 
areas, vast sinkings and upheavals of the land, going grandly on 
through the slow lapse of centuries; the stranding and piling up 
of icebergs on shoals and coasts; the southern migration and sub- 
sequent retrogression of northern organisms; and the gradual dawn 
of softening climatic influences, coupled with the shrinking back of 
glacial forces to within their present limits. 
It was thus by observations conducted in northern lands and seas, 
and in Alpine valleys, that the true nature of our drift phenomena 
became gradually elucidated. Professor Ramsay, in the attractive 
essay now before us, has placed in striking parallel—not from the 
descriptions of others, but from personal observation and research— 
some of the glacier valleys of Switzerland, with the romantic Pass 
of Llanberis and other valleys of North Wales. Commencing with 
the Swiss valleys, he lays before us a rapid but graphic sketch of the 
glaciers of the Aar: shewing how incontestible is the fact, that, vast 
as are these glaciers now, they shrink into insignificance when com- 
pared with their extension in former times. The same fact is obsery- 
able, indeed, with regard to almost all the glaciers of these Alpine 
valleys. On this subject, after mentioning some modern instances 
of the advance and retreat of glaciers, Professor Ramsay remarks :— 
** But all such historical variations in the magnitude of glaciers are 
triflmg compared with their wonderful extension in pre-historic 
periods. There is perhaps scarcely a valley in the High Alps in 
which the traveller, whose eye is educated in glacial phenomena, will 
not discern symptoms of the former presence of glaciers where none 
now exist; and in numerons instances, far from requiring to be 
searched for, these indications force themselves on the attention by 
Signs as strong as if the glacier had disappeared but a short time 
before the growth of the living vegetation. So startling, indeed, are 
these revelations that for a time the observer scarcely dares to admit 
to himself the justness of his conclusions, when he finds in striations, 
moraines, roches moutonnées, and blocs perchés, unequivocal marks 
of the former extension of an existing glacier, a long day’s march 
