78 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 
fest that the bottom of the ocean in which the lower beds of the 
mountain limestone were deposited, must (since they contam many — 
organic remains) have gradually subsided during the deposition of 
the whole Carboniferous system. A gradual subsidence of this kind 
to a greater or less extent may be regarded as a necessary consequence 
of the state of dislocation in which the disturbed mass of the older 
rocks beneath the sea had been left by the previous subterranean 
movements. During the subsequent repose the subsidence would 
probably continue for a great length of time, as a consequence merely 
of gravity ; in the present case the subsidence would be increased by 
the superincumbent weight of the newly-deposited matter. 
Fig. 4 is intended to represent a section of the district immediately 
after the deposition of the Carboniferous system, and before its ele- 
vation. The system is represented as divided into two portions, the 
lower consisting principally of limestone, and the upper of the mill- 
stone grit and coal. Both portions are supposed to extend over the 
whole tract, though with less thickness about L, the present locality 
of the Lake district. If it be conceived to have existed there in still 
smaller thickness, or even to have been entirely wanting, it will make 
no material alteration in my view of the subject, so long as we sup- 
pose there to have been no considerable relative elevation of that por- 
tion of the surface of the grauwacké group. 
(4.) This process of deposition was succeeded by those great move- 
- ments by which the Carboniferous system was broken up and ele- 
vated. Fig. 5 shows the position which it is supposed the beds would 
have assumed after their complete elevation, supposing no part of 
them to have been removed by denuding causes durmg that moye- 
ment. The figure represents, therefore, the effect of the elevation 
only, and not the combined effect of elevation and denudation, which 
probably went on simultaneously for a very long period of time. At 
S the great Penine fault is indicated, and at L are three faults, intended 
to represent generally those formed in the Lake district by this ele- 
vation. Fig. 6 represents, by the dotted lines, the mass supposed to 
have been carried away by denudation durmg the time which inter- 
vened between the commencement of this elevation and that of the 
deposition of the magnesian limestone, or magnesian conglomerate and 
new red sandstone. There is nothing hypothetical in this extensive 
denudation, for in numerous instances we have distinct evidence of 
the existence of enormous faults in all parts of our coal and mountain 
limestone districts, without any elevation (such as represented at L 
and 8) of the existing surface on one side of the fault as compared 
with that on the other; proving, in such cases, denudation like that 
represented by the dotted line in the diagram. This might be effected 
in the case before us in either of the two ways above-mentioned in 
(2.), according as the movement by which the mass was dislocated, 
elevated its surface above the sea or not. 
It may be doubted whether the surface of the tract about the pre- 
sent lakes was entirely submerged beneath the sea, as represented in 
fig. 6, at the epoch then referred to. It is not essential to any ob- 
ject I have in view, to assert that it was so. The same reasoning, 
