DALY: PHYSIOGRAPHY OF ACADIA. 81 



rate. These would show a common sky-line when viewed from some 

 commanding peak. Such a sky-line is supposed by Tarr and Smith to 

 be the one mistaken in some regions for the residual profile of a finished 

 peneplain, dissected after a new uplift. If the " beveling " hypothesis 

 be established, it is claimed that, in such cases, we are no longer forced 

 to believe in the repeated occurrences of land-surfaces that stood near 

 the sea-level through the enormous period of time occupied during an 

 old age sufficient for peneplanation. At the same time, tilting forms 

 a superfluous supposition. 



But, even without questioning the conclusion that downstream wast- 

 ing will be so very much more rapid than upstream wasting, we may 

 believe that the " beveling " hypothesis cannot explain the topography 

 of the Southern Plateau. In the first place, the cross section of any 

 of the more important interstream areas indicates a striking discon- 

 tinuity of slope. Most of the sky-line profile is flat and is evidently 

 not in the position of a graded slope where the determinant of the 

 grade is either of the two adjacent streams. From this broad, flat 

 upland there is on each side a sudden transition to the steep slope im- 

 mediately overlooking the stream, — a sharp decline characteristic of a 

 young valley. The frequent repetition of such an arrangement of slopes, 

 the predominance of broad, undissected interstream facets developed 

 indifferently on diverse rocks and structures in no sympathetic relation- 

 ship with the existing stream-courses, is most simply explained by re- 

 ferring the land-form to two cycles. Secondly, the lack of accordance 

 between the slant of the upland facet and the trends of the larger 

 (pre-glacial) valleys seems to invalidate the idea of " beveling " in 

 almost as complete a manner. We cannot doubt that one of the largest 

 pre-glacial river-systems of Acadia lay in what are now the more or less 

 completely drowned valleys of the Bay of Fundy and of the Cornwallis- 

 Annapolis lowland, both of which trend at a high angle to the direction 

 of slant of the plateau. Yet, by the hypothesis of " beveling," we 

 should expect the northern edge of the plateau rock lying adjacent to 

 these master-valleys to be graded to at least as flat a slope as those in 

 the interior of the present upland, and we should look for a gradual fall 

 of the " South Mountain " divide from Wolfville southwestwardly. 

 We have already seen that neither of these conclusions corresponds 

 to the facts. 



Field evidence, then, seems to exclude the newest of the three 

 hypotheses which have, up to the present time, been suggested for such 

 a case. Whether marine or subaerial denudation must be finally 



