476 J, W. SPENCER — PLEISTOCENE SUBMERGENCE. 



not probably synchronous, although they have taken place in the most 

 recent geological times. 



This paper must of necessity be imperfect, as it is the first attempt to work 

 out the detailed evidence of the recent terrestrial subsidence from records in 

 ancient shore-lines of the Great Lake region, many of which have only 

 recently been reported by the writer. All of the phenomena cited show 

 that in recent geological times there have been gigantic movements causing 

 the earth's crust to heave to and fro, producing conditions which have greatly 

 modified the physical features, climatic conditions, and distribution of life. 



