72 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 
surface, arising from the protrusion of the harder beds. In fact, the 
junction may be made out along nearly the whole boundary of the 
district with sufficient accuracy to justify, I think, this conclusion. 
This perfect evenness of the grauwacké surface is also beautifully ex- 
hibited along the north side of Ingleborough and round the western 
flank of Whernside. There can be little doubt, I conceive, of the 
bottom of the sea on which the mountain limestone was deposited 
having been very approximately a plain surface. Moreover, if the 
surface on which the general mass of this limestone was deposited was 
very nearly plain, it must also have been very nearly horizontal. The 
truth ofthis proposition depends on the conclusion that, whatever be 
the depth at which organic beings of any proposed class may exist in 
the ocean, it cannot be a matter of indifference whether the individuals 
of that class exist at the depth of a few feet, or at that of several thou- 
sands. For, assuming this, if a stratum be characterized throughout 
by similar organic remains, it follows that the different parts of the 
stratum could not have been deposited at very unequal depths, and 
consequently, if the surface was nearly plain and even and of sufficient 
extent, it must have been also very nearly horizontal. Such, there- 
fore, I conclude to have been the case with the surface on which the 
lower beds of the mountain limestone were deposited. 
5. This reasoning applies directly only to those portions of the 
district in which the surface of junction has been preserved by the 
superincumbent limestone. There still remains the question—whether 
the limestone originally extended over the central part of the district. 
That it extended over a considerable portion of it is proved (as shown 
by the most cursory inspection) by the height which it now occupies 
at several points of its present boundary, as for mstance on Kendal 
Fell on the south-east, between Penrith and Keswick on the north- 
east, and on the west near Egremont. To form an opinion on this 
point, let us conceive an imaginary surface as a continuation of the 
general surface of junction (independently I mean of merely local ir- 
regularities) to be carried over the central area from the present basset 
of the mountain limestone, and so as just to touch the summits of the 
highest mountains. 
The inclination of this imaginary surface in many places would not 
exceed 2°, would rarely amount to 3° (about one in twenty), and 
would never, I think, exceed 5°*. This greatest inclination would 
take place only on the north of the Skiddaw group. Now the incli- 
nation of the limestone beds near the boundary of our district is 
generally considerably greater than 2° or 3°, sometimes amounting 
(on the west) to 20° or 30°. Hence it seems highly probable that 
* There are few points on which an observer is more likely to receive erroneous 
impressions than the angular elevation of the sides of mountains. A good model, 
on a true scale of heights and distances, is the surest safeguard against such im- 
pressions. At Keswick there is an excellent model of this kind, which I cannot 
too strongly recommend to every one who wishes to gain an accurate conception 
of the geography and physical structure of the district of the Lakes. It is the 
work of Mr. Flintoft, by whom it is now exhibited to visitors at Keswick. It 
originated, I believe, with himself, and has been completed by his unaided exer- 
tions. 
