IN THE WHITE MOUNTAINS. 557 
of an eastern glacier moving westward may be seen near the 
Twin Mountain House ; but I have not examined that region 
with sufficient care to give minute particulars. 
All these moraines rnd traces of local glaciers overlie the 
typical or northern drift so-called, wherever the latter has 
not been entirely swept away by the local glaciers them- 
selves; thus showing that the great ice sheet was anterior to 
the local glaciers, and not formed by a spreading of smaller 
preexisting glaciers. At least, wherever I have recognized 
traces of circumscribed glaciers in regions where they no 
longer exist, it has always appeared to me that the minor 
areas covered by ice were remnants of a waning sheet of 
greater extent. If the glacial period set in by the enlarge- 
ment of limited glaciers already formed and gradually 
spreading more and more widely, as Lyell and the geologists 
of his school suppose, the facts which would justify such a 
view are still to be made known. I have not seen a trace of 
them anywhere. On the contrary, throughout the ranges of 
the Alps, in the Black Forest, the Vosges, as well as in the 
British Islands, in Scotland, Wales and Ireland, I have 
everywhere satisfied myself that the more extensive the 
glaciated areas, indicated by polished surfaces and moraines 
in any given locality, the older they are when compared with 
glacial phenomena eircumscribed within narrower limits. 
It therefore follows from the facts enumerated above, as 
well as from a general consideration of the subject, that the 
local glaciers oF the White Mountains are of more recent date 
than the great ice sheet which fashioned the typical drift. 
On another occasion I hope to show that the action of the 
local glaciers of the White Mountains began to be circum- 
scribed within the areas they covered, after the typical 
drift had, in consequence of the melting of the northern 
ice sheet, been laid bare in the Middle States, in Massachu- 
setts and Connecticut, after even the southern portions of 
Vermont, New Hampshire and Maine had been freed, and 
when the White Mountains, the Adirondacks and the Ka- 
