The Peneplain.— Davis. 239 
the coastal border, such as ordinarily accompanies recent up- 
lift, unless the postglacial coastal plain of Maine be so con- 
sidered; and that would hardly be permissible, for the existing 
valleys were eroded before the plain was formed. 
C 6. TJie alteriuite hypothesis takes no aeeount of buried -^ 
peneplains. Professor Tarr's hypothesis, which "calls merely 
for a greatly reduced, but still markedly irregular surface" 
(p. 370), entirely fails to meet the case of well preserved pene- 
plains, like that of the Piedmont belt in Virginia, and even 
more entirely fails to meet the case of buried peneplains, such 
as have been described above. The first example cited, that 
of the even floor on which the Carboniferous rocks rest in the 
Colorado canyon, is entirely beyond the reach of a 'theory 
that does not carry subaerial denudation further than the stage 
of maturity. If refuge is taken in the theory of marine abra- 
sion, the several examples in France and Bohemia, where ma- 
rine abrasion is excluded, remain to be explained. It must 
therefore be repeated that it is a matter of regret that a theory, 
intended to supplant the theory of peneplanation, should have 
been framed chiefly with respect to the rugged uplands of 
New England and New Jersey, and without sufficient consid- 
eration of the many other examples of better peneplains, buried 
and unburied, of which modern geological and geographical 
writings contain abundant descriptions. 
The preparation of this essay has been greatly aided by the 
kindness of my geological and geographical colleagues in 
Edinburgh, London, and Paris. The completion of the essay 
in southeastern France has made it impossible to cite, as fully 
as r should like, certain pertinent examples, to which, how- 
ever, there may be opportunity of returning if fuller con- 
sideration of the peneplain idea is called for by a continuation 
of this discussion. ' 
Cannes, France, December, i8g8. / y^ 
