Reviews—Glacial History of Nantucket and Cape Cod. 137 
II.—Tue Gracrat History or Nantucket AND CapE Cop: WITH AN 
ARGUMENT FOR A FOURTH CENTRE OF GuAcrtaL Dispersion in Norte 
America. By J. Howarp Wutson, A.M., Ph.D. x + 90 pp., 
with 38 plates (29 photographic views and 9 maps) and 13 text- 
figures. (New York, The Columbia University Press; London, 
Macmillan & Co.: 1906. Price not stated.) 
IW\HIS book, issued as No. 1 of the Columbia University Geological 
Series, is essentially a geological ‘paper’ of the usual type, 
published in a form unusual in this country. It is well printed on 
thick unglazed paper, profusely illustrated, and neatly bound; but the 
subject-matter, though scientifically valuable, is of comparatively 
restricted interest, and except in the United States would not have 
been deemed sufficient either in quantity or substance to reach the 
dignity of separate publication in this form. 
The paper deals exhaustively with the glacial deposits—the only 
visible formation — of the small island of Nantucket and of the 
adjacent peninsula of Cape Cod, with notes on other islands in the 
neighbouring part of the Massachusetts coast. This area had been 
previously investigated by Shaler, Woodworth, and others, but the 
author believed that the field was rich enough to yield a second crop. 
The principal outcome of his work is the theoretical conclusion—of 
interest mainly to the American glacialist—that the latest glaciation 
of the region was effected by an ice-sheet radiating from a hitherto 
unrecognized centre, lying to the east of the Labrador sheet and 
moving south-westward to the Massachusetts coast from Newfoundland. 
The shelly drift of Sankaty Head, Nantucket, receives particular 
notice, the author having obtained by excavation a large series of 
shells and a fully detailed section of this stratified deposit of sand and 
gravel. He has previously published an account of this work in the 
Journal of Geology (Nov.—Dec., 1905), his conclusion being that the 
beds are of normal marine accumulation, and that although the shelly 
deposit is only 8 feet in thickness it embraces indications of changing 
condition ; the lower layers containing shells of a shallow-water type 
and distinctly southern range, while the upper layers denote con- 
siderably deeper water and hold a decidedly northern fauna. The 
shell-beds are supposed to indicate an Interglacial episode, but the 
evidence on this point is admittedly weak, as the underlying clay is 
no longer visible; and though considered by the author to be probably 
of glacial origin, this clay has been assigned by some of the previous 
workers to the Cretaceous system. 
In view of the much-discussed problem as to the level of the land 
during the Glacial period, it is interesting to note that ‘‘ from evidence 
gathered all over the island we know that the land stood not far 
from its present level when the ice-front occupied the Nantucket 
position ’’ (p. 30). 
In his general discussion of the drift, the author recognizes as the 
principal features in Nantucket geology—(1) a chain of ‘‘ Kame 
Hills,” evidently an old line of moraine, which does not, however, 
mark the extreme limit reached by the ice-sheet; (2) ‘‘the fosse,” 
a low area in front of the Kame Hills, supposed to have resulted from 
the presence of the marginal ice; (3) ‘‘ the ice-contact slope,”’ rising 
