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changes the whole of the Carboniferous rocks undergo as they are 
traced from N.W. to S.E., that some of these thin impure limestones 
may represent the thin edges of beds of limestone of Upper Car- 
boniferous age, which occur in Belgium and other areas to the 
south-east. We have too long regarded the advent of the North 
of England Millstone Grit as marking the close of the Carboniferous 
Limestone. Yet the deposition of limestone must have gone on 
even into Coal Measure times, only that the area of deposit was 
carried, by the gradual advance of the delta, farther and farther 
towards the south-east as time went on. If these Belgian Carbon- 
iferous Limestones be regarded (as suggested here for the first 
time) as being contemporaneous with the British Millstone Grit 
and Coal Measures, it would serve to explain the marked 
discrepancy between the faunas of the limestones in the two areas. 
The difference would be due, not so much to different conditions, 
as to difference in age. 
Of the remaining limestones of Cumberland and Westmorland 
not much need be said here. Long after all the Carboniferous 
rocks were formed they underwent much disturbance, upheaval, 
and denudation ; and part of the Lake District was for a time 
temporarily exposed. Upon the upturned edges of the older strata 
were afterwards laid down in succession (1) the Lower New Red, 
(2) the Magnesian Limestone, (3) the Upper New Red, including 
the Lower Gypseous or Bunter Marls, the St. Bees and Kirklinton 
or Bunter Sandstones, and the Keuper or Stanwix Marls. Later 
on, ferriferous and magnesian solutions, percolating downward 
into the older rocks from these Red Rocks, gave rise to the 
dolomitization of many of the older calcareous deposits ; and at the 
same time, replaced much of the calcareous matter by H#MATITE. 
This process may even be going on now. 
After the deposition of the Red Rocks, whose higher members 
certainly overspread the newly-exposed Lake District, followed the 
Jurassic period. Rocks of this age almost certainly overspread 
the whole of the North of England, Ireland, and the South of 
Scotland. The Lias Limestone of Great Orton is the last 
remnant of these undenuded. 
