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BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



rises further uorth by a faded scarp of gentle slope. Sandstone ledges 

 are abundant along the western base of the spur ; they are unusually 

 steep, in part because of the eastward dip of the strata, and in part be- 

 cause of a certain amount of under-cutting by the Westfield when it ran 

 beneath them. The eastern side of the spur is not trimmed close to the 

 defending ledges, but illustrates the uusymmetrical relations shown in 

 Figure 31. Widely as the river has swung from side to side in the 

 basin further west, it was here strongly constrained. Not only so : 

 Westfield river has been somewhat impelled northward by the 



Fig. 38. 



entrance of Little river from the south (west of the area shown in 

 Figure 38) ; and it is probably in part at least on this account that the 

 basin has been so well broadened northward ; } r et on every sweep or 

 swing against the sandstone reef, the river was not only restrained 

 from further northward conquest at that point, but was deflected 

 obliquely southward across the valley. It is very probable that the 

 excavation of the subordinate basin, C, is due to this cause, for it is 

 opened further to the south than to the north. Three strong south- 

 ward loops of the river, D, E, F, (including the present one) are here 

 recorded ; and it can hardly be by chance that the river has thus 



