318 K. A. DALY OSCILLATIONS OF LEVEL 



Munthe's able summary of the case in northwestern Europe is clearly 

 of great significance for American geologists. Jamieson's hypothesis 

 attains new dignity, as it is seen to have been quite independently adopted 

 to correlate and explain many facts observed in the belts peripheral to 

 two different ice-caps. 



Summary 



Many lines of evidence seem to support Jamieson's suggestion that 

 the earth's crust has been plastically deformed by glacial loading and, 

 in the reverse way, by unloading through the melting of ice-caps. Study 

 of the recently emerged zone in New England and of the specific dis- 

 tribution of plants and animals in Newfoundland indicate the probable 

 existence of a late Glacial to Eecent bulge of land near the edge of the 

 continental shelf. If that bulge ("Georges Bank Laud") were flattened 

 because the glaciated area on the northwest rose in consequence of un- 

 loading (ice-melting), one may reasonably expect field evidences of 

 similar peripheral subsidence west of New England. Deformed lake 

 strands, the submarine channel of the Hudson Eiver, the "deeps" of the 

 Susquehanna Eiver, and Pleistocene drainage rearrangements of the 

 mai'ginal belt west of New Jersey offer relevant topics for discussion. In 

 no case can the evidence be regarded as final, for none can be discussed 

 intelligently without making at least one unproved assumption. A lead- 

 ing and general difficulty lies in the uncertainty as to the position of the 

 zero isobase corresponding to each subsidence and each uplift, respectively 

 induced by glaciation and deglaciation. Jamieson's hypothesis thus 

 leads to many questions without answers ; precisely for that reason it has 

 value if it stimulates further field-work by experts. Especially because 

 of Munthe's positive results in Baltic lands, the hypothesis can not fail 

 to be seriously and actively entertained in America. 



