132 
HUGHES : INGLEBOROUGH. 
The sea that planed off the top of Ingleborough lashed the 
rocky base of the Lake Mountains, which then, however, did not 
rise more than a thousand feet above its level. But it is to be 
feared that the denudation which has been going on ever since 
that time has completely swept away whatever traces were left 
upon that rocky shore. However, there we see shores which 
were washed by the sea that planed off the top of Ingleborough. 
We have, as I have already pointed out, another fragment 
of that ancient land in North Wales, where the Snowdonian 
group represents it, attaining about the same height, viz., a little 
over 3,000 feet, while all round it there stretches the great 2,000 
foot sea-plain, corresponding to that of which the top of Ingle- 
borough forms part. 
Just consider for a moment what this means. To reconstruct 
the upper sea-plain so as to unite Snowdonia with Lakeland you 
must put back 1,000 feet of rock over all the north-west of 
England and the whole of Wales, as well as over the intervening 
sea, in which the mountains of the Isle of Man are the only 
relic of the former extension of either sea-plain over this area. 
Now, denudation implies a corresponding deposition. Where 
is the great formation built up of the material carried down to 
the sea when the Ingleborough sea-plain was formed ? It must 
be later than Carboniferous, because Carboniferous rocks were 
being planed off. Was it Jurassic with its Poikilitic basement 
bed, or was it Cretaceous, or does it belong to that age of 
volcanic activity and vast denudation, the Miocene? Or must we 
refer it to the time of great erosion which immediately preceded 
glacial conditions here, and so make it correspond to the Osarkian 
or to the Champlain of America? 
As we look out south over the range of hills that trends 
away to the east from Lancaster and to the flat-topped isolated 
mass of Pendle, we ask, have we here other outlying fragments 
of our great West Riding Plateau ? But we soon find that their 
summits do not attain to anything like the level of Ingleborough. 
This difference of elevation is too great to allow us to consider 
them now as part of the West Riding Plateau, but may we 
