388 R. A. Daly—Post-Glacial Warping of 



England. Incomplete as this field evidence is, it suggests 

 a reason why the post-Glacial deformation of Newfound- 

 land has been more controlled by the adjacent, masterful 

 cap centering in Quebec than by its own load of ice ; such 

 a relation would be expected on the recoil theory of the 

 deformation. 



Recent Droivning of Southern Newfoundland and of 

 Southern Nova Scotia. — Yarmouth, Nova Scotia, clearly 

 lies outside of the area uplifted since the Glacial period. 

 The zero isobase cuts across the shore somewhere between 

 that point and Digby, where the uplift has been about 

 40 feet. A visit to Pictou Landing on Northumberland 

 Strait showed that this locality lies south of the zero 

 isobase.'^ The 1920 observations thus confirm the essen- 

 tial accuracy of De Geer's map, published in 1892. With 

 the exception of a small area in the northwest, Nova 

 Scotia has not been, uplifted since the latest driftsheet 

 was deposited. On the contrary, post-Glacial drowning 

 is manifest all along the coast from Yarmouth to Hali- 

 fax, and at Sydney. The same process has apparently 

 affected most, if not all, of Cape Breton Island, and also 

 the Newfoundland shore south of the zero isobase. 



Causes of the Droivning. — The positive movement of 

 the sea-level is in part referable to its general rise as the 

 Pleistocene land-ice melted. If the rise of the glaciated 

 tract north of the zero isobase was largely an elastic 

 reaction of the earth, additional drowning outside the 

 zero isobase is to be credited to gravitational disturbance. 

 Under the weight of the ice-cap the material of the earth's 

 interior was condensed. Each radial element was com- 

 pressed Avith consequent lowering of its center of gravity. 

 The observed lag in uplift implies that this condition 

 existed for some time after the ice melted away. The 

 horizontal component of the mass attraction exerted by 

 the radial element on the ocean water was less before 

 the elastic upheaval than after that upheaval. The mass 

 of the element was not changed by its expansion, but the 

 distribution of the mass was changed. The fraction of 



*^W. H. Twenhofel (this Journal, vol. 28, p. 147, 1909) found raised 

 beaches, at altitudes above sea of about 25, 75, and 125 feet, in the shore- 

 belt only 25 miles east- of Pictou Landing. The present writer had no 

 opportunity of ^asiting Twenhofel's locality (Arisaig). Since the latest 

 drift-cover around Pictou has evidently not been washed by the sea, it is 

 not easy to understand Twenhofel 's results, except on the assiunption that 

 the Arisaig benches antedate the last glaciation. 



