223 
removal of great masses of rock by sea denudation. The 
gigantic cliffs at the north-east side exist, not because any- 
gigantic fault has brought them up from a previous lower 
level, but because they have been left by the cutting away 
of the strata which once filled the wide valley of the Wharfe, 
which undoubtedly is a valley of excavation or denudation. 
The top of Eombold's Moor has likewise been evidently 
left by denudation. It is exceedingly probable that it was 
once covered by a great thickness of Coal Measures, which 
have disappeared, with, the exception of the patch composing 
the upper part of Baildon Hill. The Coal Measures have 
evidently been thrown up and divided by the Pennine range 
of hills between Lancashire and Yorkshire — Lancashire 
thrown to the west and Yorkshire to the east. 
One thing is certain, that more or less rock has been 
removed from the top of Eombold's Moor. This is demon- 
strated by the terraces or plateaux, which are bounded by 
low escarpments or cliff-lines, the strata of which must once 
have extended much further than at present. 
On the north-east side of the moor there are two very 
distinct terraces, above the principal cliff-line which sur- 
rounds a great part of the moor. Their scarps consist of a 
steep slope, with bare rocks at intervals, and their platforms 
of clay, containing stones more or less rounded. The lower 
terrace runs back into the higher towards the south-east, as 
successive beaches on a rising sea-coast are cut back into 
each other at the present day. (Plate I., fig. 2.) 
I feel constrained to agree with Mr. Mackintosh, in his 
paper read last spring at Sheffield, in regarding all such 
terraces as having been formed by the sea, during the 
emergence of the land, either gradually, or intermittingly, 
or in the form of occasional sudden upstarts of smaU vertical 
extent. I likewise agree with him in looking on large 
valleys such as the Wharfe as the effect of sea action ; at 
