ELISHA MITCHELL SCIENTIFIC SOCIETY. 49 



o-lacial submerg-ence amounting- to 400 feet in the 

 northern part of the field (New Jersey) and almost 

 nothing- at its southern limit. 



Other Quarternary formations occur in the southern 

 field, of which the shore-line limit lies 10 to 50 miles 

 inland, from South Carolina to Florida. Here the 

 Quarternary forms one third of the peninsula (the 

 southern end) and thence the division line swing-s 

 along- the Gulf coast where it marks off a border 

 formation almost equal in width to the similar strip 

 along- the Atlantic states. 



Far the larg-est area of land surface which has been 

 added to the Atlantic border is seen to to be of Terti- 

 ary ag-e. On the inner border of this a narrow strip 

 of Cretaceous and on the outer edg-e a thin layer 

 of Quarternar}^ sediments, make up, taken with the 

 Tertiar}', practical!}^ all that the continent has gained; 

 and the area represents the final amount of recession of 

 the Atlantic shore-line during- recorded g-eolog-ical 

 time. North of Cape Cod the result of oscillation 

 so far has been on the other side, and the coast-line 

 now probably stands farther in upon the land than at 

 the beg-inning- of recorded time. Here we have lost 

 rather than g-ained continental area. 



The subjoined map attempts to represent the Atlan- 

 tic shore-line histor}" in the order in which I have 

 attempted to compile it in this paper. The study has 

 necessaril}^ been crude and incomplete in its nature 

 and is offered as an introduction to a more critical and 

 extended study which may be undertaken later on. 



references: 



LeConte. — Eletnents of Geology. 3d edition. 



Walcott, C. D. — Cambrian Correlation Papers; Bulletin 81, U. S. 

 Geol. Survey, (Atlantic coast Province). 



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