REVIEWS 853 
tion of very notable changes in the level of these beaches. A former 
relative rise of the surface to the northeast is not only amply demon- 
strated, but a progressive fall of the surface at the north at later stages 
until it reached its present attitude is fully made out. The move- 
ment appears to have been steadily progressive and systematic. The 
possible causes of these changes of levels are discussed, embracing 
gravitation toward the ice-sheet which, while measurably effective, is 
found quantitatively insufficient, changes in the temperature of the 
earth’s crust which is also regarded as insufficient, and epeirogenic 
movements apparently dependent in part upon glaciation, which is 
regarded as the essential agency. In this connection the author 
extends his discussion widely, treating of the preglacial elevation of 
North America, as shown by fiords and submarine valleys and of the 
late glacial or Champlain submergence shown by fossiliferous marine 
beds overlying glacial deposits, and from these he endeavors to deduce 
the Pleistocene dscillations embracing those which were independent 
of glaciation as well as those dependent upon it. He maintains his 
well-known views regarding the dependence of glaciation essentially 
upon epeirogenic movements. 
The monograph closes with chapters on the artesian and common 
wells of the Red River valley and the agricultural and mineral 
resources of the area of Lake Agassiz. There are added appendices 
giving the courses of glacial striz and notes on aboriginal earth works 
within or near the area of the lake. The whole material is worked 
out with care and great detail and constitutes a very important con- 
tribution to Pleistocene history in both its glacial and its lacustrine 
aspects. T.Ca@ 
Catalogue of the Tertiary Mollusca in the Department of Geology, 
British Museum (Natural History). Part 1. The Austra- 
lasian Tertiary Mollusca. By GreorGe F. Harris, F.G.S. 
407 pp., 8 pls. London, 1897. 
The British Museum, which has in process of publication cata- 
logues of its great collections, has lately started a new series upon the 
Tertiary Mollusca, under the editorship .of Professor Harris. The 
first volume dealing with the Australasian forms has just made its 
appearance. The acquisition by the Museum at different times since 
