REVIEWS 323 
The memoir concludes with two appendices and an extensive 
bibliography. Appendix I is entitled “‘On Ground Air and its Rela- 
tions to Atmospheric Carbonic Anhydride,” in which some very 
interesting figures are given and important conclusions drawn. 
Appendix II is on ‘““A Comparison of the Results of Determinations of 
Carbonic Anhydride by Pettenkofer’s Original Process, and the 
Method proposed by Professor Letts and Mr. Blake, and on the 
Errors incidental to Pettenkofer’s Process.” By William Caldwell. 
The bibliography contains 3c5 entries, proportioned as follows: 
German 128, French 98, and English 79. 
THomas L. Watson. 
DENISON UNIVERSITY, 
Granville, O. 
Om de Senglaciale og Postglaciale Nivaforandringer I Kristiania- 
feltet (Molluskfaunan). By W.C. Bréccrr. Separaftryk af 
Norges geologiske underségelse No. 31. Kristiania, 1901. 
TuHIs volume concerns itself primarily with the study of the faunas 
of Pleistocene time in the vicinity of Christiania, and with the changes 
of level which the character and distribution of these faunas indicate. 
The conclusion is reached that the deep sea bottom adjacent was 
something like 2600” higher than now when the great ice sheet was 
on, this inference being based on the existence of shallow water fossils 
at great depths in the ‘‘ Norwegian sea.” 
At the end of the last interglacial epoch the land is thought to 
have been some 1o0o™ higher than now, and that this epoch of eleva- 
tion continued into the time of the last ice covering. As the ice of the 
last epoch began to melt, the land began to sink, the subsidence con- 
tinuing for some time after the retreat of the ice began. At the time 
of the formation of the outermost moraines, the land was too™ to 125™ 
lower than now. This was the time of the deposition of the older 
and younger yoldia clays and of the older arca clay. While the ice 
retreated to the second series of moraines, subsidence continued until 
the land was 150” to 16c™ below its present level, when the outer- 
most moraines of the second series were formed, and 180™ to 185™ 
below its present level during the formation of the innermost moraines 
of the same series. There was further sinking as the ice receded to its 
third halting place, and at that time the land stood about 200” below 
