408 THE JOURNAL OF GEOLOGY. 



posits. This is abundantly proven in the St. Lawrence and 

 Champlain valleys, where clays containing marine fossils occur 

 up to a certain horizon and record a Pleistocene invasion of these 

 depressions by the sea. If the adjacent Ontario basin was 

 occupied by the sea about the same time that the Champlain 

 valley received its filling of c'ays containing marine fossils, there 

 is every reason to believe that the deposits and their contained 

 fossils in each basin would have been essentially the same. 



One of the best known of the ancient shore lines about Lake 

 Ontario has an average elevation of approximately 500 feet 

 above the sea. If the sea had access to the basin at the time 

 this breech was formed, then at corresponding horizon without 

 the basin especially, to the south and southeast, where the full 

 force of the Atlantic's waves would have been felt, there should 

 be still more prominent beaches. 



Many well-defined shore lines in the Laurentian basin are 

 much higher than the one just referred to, and if these were also 

 formed during various stages of submergence, as has been 

 claimed, it is evident that ocean beaches and ocean sediments 

 of Pleistocene age should be looked for over nearly the whole 

 of the eastern part of the United States. The student may 

 easily answer this question for himself, and thus perhaps make 

 a contribution to the subject here treated. 



In the investigation here outlined, the work of previous ob- 

 servers should not be ignored, and every plausable hypothesis 

 that has been advanced to account for the facts observed should 

 be carefully tested. In writing these pages I have not quoted 

 the writing of others, for the reason that a discussion of evidence 

 has not been the aim in view, and also because the writings 

 examined are so numerous that justice could not be done them 

 in the space at command. That the literature relating to the 

 subject is voluminous is indicated by the fact that an annotated 

 bibliography of the Pleistocene history of the Laurentian basin, 

 now in preparation, already contains over 200 entries of indi- 

 vidual papers. Israel C. Russell. 



