ISOSTATIC MOVE^EENTS OFF NEW ENGLAND COAST 309 



"Although the wide, level plains of marine clay were deposited in situations 

 open to the disturbing influence of river, tidal, and storm currents, the clay is 

 characteristically uniform in composition and texture and in the attitude of 

 its bedding. Therefore the clay must have been deposited in quiet water, 

 namely, in this instance, water whose surface was considerably above the 

 levels up to which the clay plains were built and in consequence probably deep 

 enough to submerge the moraine." ® 



During so long a time the waves of the open Atlantic should have made 

 an easily read record at or near the highest strand-level, instead of the 

 obscure markings actually found. 



CONCLUSIOli 



Thus the details of the highest strands, as well as the general character 

 of the emerged belt in N"ew England, seem to indicate that the rollers of 

 the open Atlantic did not pound the coast during most of the period of 

 submergence, although they may have done so during the last quarter of 

 the uplift. In the field several hypotheses were entertained in explana- 

 tion. It is conceivable that, if the ocean were locally frozen during most 

 of the period of uplift, strong wave-action would be prevented. That this 

 was not the dominant condition is suggested by the phenomena of the 

 Labrador coast, where annual freezing is likely to have been more pro- 

 longed than along the New England coast. Similarly, the possibility of 

 protection of the land by an offshore tongue of the great ice-cap was 

 considered, but dismissed for good reasons, which need no recounting on 

 the present occasion. Jamieson's idea seemed much more promising than 

 any other, and later study has confirmed the impression gained in the 

 field. If his h3'pothesis is in line with the truth, the outer part of the 

 continental shelf should have been forced up by the weight of the Labra- 

 dor ice-cap. The Gulf of Maine would then have become a nearly land- 

 locked arm of the ocean, elongated parallel to the existing coastline and 

 so narrow that its waves could attain the energy of a lake but not that 

 of the open ocean. Extending, theoretically, from Cabot Strait or farther 

 northeast to New Jersey, this bulge of new land would include Georges 

 Bank, and it may for convenience be called Georges Bank Land. 



Because of the narrowness of the shelf off northeastern Labradoi-, 

 similar moderate bulging would not there form dry land; hence the 

 emerged belt of Labrador shows the effects of wave-action stronger than 

 those in the New England belt. 



This speculation was seen at once to harmonize with Fernald^s view 

 that the flora of Newfoundland is best explained by assuming a former 

 more or less continuous land-mass of the coastal plain type between New 



» F. J. Katz and A. Keith : Professional Paper No. 108 B, U. S. Geol. Survey, 1917, 

 p. 27. 



