246 THE GLACIAL OR ICE EPOCH. 



ever undergone a similar glaciation; and if so, whether 

 it took place, as in the northern hemisphere, immediately 

 preceding the current era.* These and similar questions 

 must receive satisfactory answers hefore a generally ap- 

 proved theory can he hoped for; and geology, in this as 

 in other instances, will "best attain her end "by a diligent 

 accumulation of facts, and the widening of her field of 

 observation. 



Such is a hasty, hut, we trust, not unintelligible Sketch 

 of the glacial or ice epoch that strange period in recent 

 geology when the frost-giant that now reigns supreme within 

 the polar circles laid his iron grasp on the northern hemi- 

 sphere down to the 40th or 42d parallel of latitude. How 

 or by what means this crisis was brought about whether 

 by some peculiar distribution of sea and land, or by some 

 great secular recurrence in the earth's planetary relations 

 theorists are not agreed; but there is no difference of 

 opinion as to its existence, and none as to the long con- 

 tinuance of its sway. Its presence is visible on every hill- 

 side and in every glen in the British Islands, Northern 

 Europe, and North America ; in the rounded eminences, in 

 the polished and striated and grooved rock-surfaces, in the 

 moraine-like mounds of gravel that bar the glens, in the 

 huge rounded and striated blocks that lie scattered over the 

 ground, and in the thick tenacious bouldery clay that en- 

 velops so much of the lower and level tracts of the country. 

 No known agent, save ice, could have produced these ap- 

 pearances ice on land, and ice on water ; ice, in fact, such 



* From recent reports by the provincial surveyors of New Zealand, as 

 well as from Mr Darwin's well-known descriptions of South America, it 

 would appear that the southern hemisphere has been subjected to a simi- 

 lar phase of ice-action. The further investigation of this as to contempo- 

 raneity with that of the northern hemisphere, would materially assist in 

 the framing of an acceptable hypothesis. 



