COLE : ORIGIN AND FORMATION OF WOLD DALES. 129 
had tended to produce the thinness of the rim itself, which is 
only 200 feet on the highest ground, as compared with 800 
feet below the clays of Holderness (see Appendix B). Nor 
did I intend to convey the impression that the present con- 
figuration of the Wolds, with its remarkable ramification of 
deep sinuous dales, was owing solely to subaerial denudation. 
This leads me to the subject of my present paper, " The 
Origin and Formation of the "Wold Dales." 
Let me first direct your attention to a sketch plan of a 
portion of the Wolds surrounding Wetwang, contained within 
the limits of a single water basin, taken from the Ordnance 
map (map A), Plate x. 
As a surface picture, it presents at first sight an exact 
copy of a mud flat abandoned by the receding tide, or of a 
river in an alluvial plain fed by innumerable tributaries * 
But it is not so in reality. One glance at the actual features 
of the country will dispel the notion. No running water 
ever did, or could, in this particular area, scoop out the dales 
with which we have to deal ; and as a matter of fact, chalk is 
not mud, and no amount of tidal actien could produce the 
peculiar features of the East Biding dales. 
Doubtless both these statements will be challenged. The 
first in fact has been already met by Messrs. Jukes and 
Geikie,f who assert that "the absence of running streams 
on the surface of the coombs and valleys of the chalk countries 
is no proof of the non-existence of these streams, but only of 
their subterranean character." If by this it is implied that 
the dales have been excavated by running water, only 
subterranean, instead of superficial, I venture to affirm that 
there is no ground whatever for the assertion. The way in 
which water is contained in the porous chalk at different levels 
of saturation (see Appendix D), the fact that the effect of 
* See Appendix C, with Maps B and C. 
t Manual of Geology, 3rd Edit., p. 458. 
