48 JOURNAL OF THE 



These approximate fi^fures are taken from careful 

 measurements by various observers of the heig'hts of 

 certain shore cliffs and marine deposits shown to be of 

 Quarternary age. I have omitted measurements of 

 various points between, and have given in the place of 

 exact figures a sort of general average of the observa- 

 tions of several persons, arranged in such a way as 

 to show the gradual increase in the amount of sub- 

 mergence going northward. 



It is difficult to reconcile the views held by various 

 geolog'ists of the amount of subsidence which took 

 place at several points along the New England coast 

 and northward. The differences depend on different 

 criteria used in the discrimination of shore-lines, dif- 

 ference in opportunity for and general incompleteness 

 of observation, etc. The consensus of opinion, how- 

 ever, as regards the Atlantic shore-line is about as I 

 have represented it. The result of such a subsidence 

 must Jiave been the submergence of parts of the Maine 

 coast, parts of Nova Scotia, Newfoundland and 

 Labrador, and of a large area extending up the St. 

 Lawrence River to the Great Lakes. 



Of the middle and southern Atlantic coast little has 

 been done in discriminating' and tracing the many 

 shore-line terraces of Quarternary age which undoubt- 

 edly exist as distinct features. Some mapping of the 

 Quarternary deposits has however been made. Of 

 these, one formation has been studied by McGee and 

 named the "Columbia" loam. It belongs especiall}^ 

 to the middle Atlantic slox3e and is older than the 

 moraine deposits of the glacial epoch. It is both 

 iluviatile and marine and is scarcely observed south- 

 ward from North Carolina, where its inner border 

 approaches the jjresent coast. It represents a brief 



