T9I4. 
Revieivs. 
155 
REVIEWS. 
THE GLACIAL PERIOD. 
The Quarternary Ice Age. By W. B. Wright. London : Macmillan 
and Co., Ltd., 1914. Pp. xxiv. -f- 464. 155 figures and xxii plates. 
Price 175. net. 
Since the publication of Professor James Geikie's " Great Ice Age " 
there has been no general comprehensive account of the state of our know- 
ledge of the glacial phenomena of the Pleistocene period, and so many 
are the newer observations and so numerous the facts recorded since the 
appearance of that volume, that Mr. Wright's work will be received with 
gratitude by those who though interested in glacial geology have been 
unable to keep pace with recent progress owing to the difficulty of access 
to much of the literature. 
The opening chapter contains a clear and useful summary of our 
knowledge of existing glaciers and their classification to which so much 
has been added in recent years by Arctic and Antarctic e^iploration. On 
page 6 is a somewhat startling statement : "A glacier terminating on 
land can for obvious reasons never form an esker." This statement is, 
it is true, somewhat qualified on a later page, but it seems to the writer 
that there are eskers in many places where it would be difficult to demon- 
strate the existence of standing water at the time of their formation. 
Attention is called to the fact that a large ice -sheet once established 
necessarily determines its own meteorological conditions, a point which 
has been largely neglected in discussing the climatic condition of the 
Pleistocene. Amongst the many matters of interest mentioned with 
regard to ice -sheets not the least in importance are their nourishment 
by snow from an otherwise clear sky, and the fact that the great Ross 
Barrier is afloat. 
Difficulties have often been raised as to the relatively small proportion 
of scratched stones in the moraines of Alpine glaciers, but these should 
be finally set at rest by the clear statement of the proportion of striated 
to non -striated stones in the different types of moraine. 
The use of the term " Giants -Kettle," on page 33 to designate the 
closed depressions in the surface of a drift sheet, and usually known as 
" Kettle Holes," is unfortunate, as the former term has already been 
adopted for a different formation. 
So much has been written lately of interglacial periods that it is good 
to have such a concise statement of the facts relating to the supposed 
three -fold arrangement of the drifts, as is here given. The glaciation of 
Ireland receives attention and recent work upon it, including much which 
is due to Mr. Wright's own labours is described for the first time. The 
question of the older and newer drifts of England is discussed, and the 
extremely slender nature of the evidence in favour of interglacial periods 
is brought into prominence. The author contrasts the monotonous sheet 
of boulder-clay of the Soiithern Midlands of England with the drumlin- 
