182 Tue Brack WATER OF DEE. 
at Carlisle we have a glimpse of the Liassic Seas, and from 
the Glacial moraines of the Pleistocene Period abundant proof 
of the geographical and climatic conditions prevailing at this 
late stage. But between these two ages there is a vast hiatus 
—a great silence-of nearly five million years. Sedimentary 
deposits are found in Central Europe which establish twenty 
ages during this hiatus in Scotland. 
If the Scottish area was not submerged during these vast 
periods, it is evident that it must have been a land surface 
which had become deeply marked by prolonged denudation. 
Assuming that the Southern Uplands were partly submerged 
under the chalky seas of the Cretaceous Period,* these soft 
deposits would be speedily removed, laying bare the old pre- 
Cretaceous land surface. 
The physical features of Galloway should thus show us 
at least four distinct phases of land sculpture accomplished 
by persistent denudation. 
1. All land forms which are due to deposition or denudation 
throughout all the pre-Cretaceous Ages. This is an im- 
portant and intricate study rapidly summarised by W. A. 
Gauld in his Galloway : An Introductory Study, pp. 24. 
2. All denudation or earth movements throughout the 
Tertiary Ages. 
3. Land sculpture due to Ice movements and morainic de- 
posits of the Pleistocene Period. 
4. Any effects accomplished in post-Glacial time. 
This paper is concerned wholly with the second group, viz., 
an examination of those physical features of Galloway which 
have been imprinted during the Tertiary Ages, especially 
those of later date—Miocene and Pliocene. 
Pre-Glacial Land Forms. 
It is evident that before a true estimate of any changes in 
land sculpture due to Glacial conditions can be obtained we 
must first be able to visualise the pre-Glacial topography of 
the particular region under study. 
From the date of the retreat of the Cretaceous Sea to the 
* The Growth of Hurope, by Professor G. A. J. Cole, p. 29; 
Building of the British Isles, by A. J. Jukes-Browne, chap. 12. 
