232 H. L. FAIRCHILD PLEISTOCENE MARINE SUBMERGENCE 



plane of the marine waters. Without study directed to this point we' can 

 not know if this correspondence has any significance, as suggesting a rela- 

 tive pause in the uplifting of the land, or whether the broader develop- 

 ment of the lower plains is merely due to the topography of the valley. 



MEANDERS; OX-BOWS 



If the terraces were the product of river work they should exhibit the 

 characteristic features due to streams, such as meanders, channels, ox- 

 bows or cut-offs, etcetera. The edges of the terraces should be frequently 

 scalloped, or cut into concavities and cusps. The writer is not aware of 

 any clear features of these kinds at the higher levels. They should occur 

 near the level of the present river and on its graded floodplain. Emer- 

 son^s map in folio 50 shows such river features in his "Terraces of Ero- 

 sion," which lie at low levels and evidently are the work of the Connecti- 

 cut Eiver; but his "Terraces of Construction," at the higher levels and 

 above the range of the present river, do not exhibit the features character- 

 istic of river work. 



KETTLES 



The occurrence of glacial kettles in the Connecticut Valley has been 

 thought to argue against deep and long submergence of the area. Kettles 

 large enough to be represented on the topographic maps are. few. The 

 largest appear on the Middletown sheet, lying east of Portland, at altitude 

 about 100 feet. Small kettles are shown on the N"ew Haven and the 

 Hartford sheets, at various altitudes up to 200 feet. The writer has seen 

 none of the kettles and can discuss them only in a theoretic way. 



The objections to long submergence of the kettles or their localities 

 would apply with more force to the river theory. The burial of the ice- 

 blocks took place at the margin of the ice-sheet. If the ice melted out 

 and the detrital cover slumped in while the mass was submerged in the 

 river, the drifting detritus would be more likely to fill and so destroy the 

 basin ; but in the more quiet standing water the basins would have much 

 better chance of escaping unfilled. It would also seem that detached ice- 

 blocks would be buried much more easily when the ice was faced by stand- 

 ing water than when the glacial outwash formed rivers. 



When kettles lie in definite terraces or other deposits that were built or 

 shaped by either stream or waves, it follows that the slumping occurred 

 subsequent to the completion of the deposit, and this may imply a long 

 time of burial of the ice before its melting. The physical factors here in- 

 volved require consideration. We assume marine submergeiice. 



