HUGHES : INGLEBOROUGH. 
129 
same general level up to the base of the Lake Mountains. These 
in their turn are obviously fragments of a higher plateau, the 
average elevation of which is some 3,000 feet above sea level ; 
while that on which we stand and which runs up to the base of 
the higher Lake Mountains is a little over 2,000 (Fig. 2). 
What is the origin of this very marked feature in the land- 
scape? We know from the geology of the district that none of 
these mountains to which I have called attention, either of those 
which touch the level of the Lake District Plateau, or of those 
which belong to the West Yorkshire Plateau, owe their present 
outline to original deposition. Nor is it due to any hard bed 
down to which denudation, sub-aerial or mixed, had reduced the 
general surface level. Not only have the valleys which separate 
one mountain from another been scooped out by various agents 
of denudation, but the tops have been planed off by denudation 
of some kind, and we do not in any case see the original highest 
beds. 
In regarding these great plateaux, we are clearly face to 
face with some phenomenon connected with the greater operations 
of Nature — something upon which depended the modelling of 
our highest mountain groups, and the interpretation of which 
ought to give us the key to the great succession of events of 
which Geology treats. 
There are, however, certain complex operations that come 
under our observation at the present day which will fully explain 
the existence of relics of wide-spread plateaux of this character. 
Along the shore we see the waves twice a day in accordance 
with wind and tide and local conditions rolling along the debris 
that falls from the clifiFs, or is carried down by streams. It uses 
the boulders and pebbles and sand as ammunition with which 
to batter down the rocks. It carries on this waste only to 
a depth of some 60 or 100 feet below sea level, for deep ocean 
currents do not contribute much to this sort of work. 
The sea is always at it, and, if the relative level of land and 
water remained steady, all the dry land would in time be carried 
down and spread out below the waters of the sea. There is 
