74 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 
animals of the same species should be able to exist at the greatest or 
the smallest depths indifferently,—so far at least indifferently, that the 
full and free performance of the animal functions should not in either 
case be impeded. It appears to me extremely improbable that any 
species of animals should possess that power of adaptation to external 
circumstances differmg so widely as light and darkness, and the fluid 
pressure of a few feet and that of several thousands. If this impro- 
bability be admitted, then is it easily seen that the validity of our ar- 
gument is unquestionable*. 
7. Faults.—I have already spoken (Art. 3) of the band of lime- 
stone interstratified with the grauwacké rocks. The dislocations of 
this band furnish the principal direct evidence respecting the faults 
of the district. Beginning with its south-western extremity, there is 
evidence of two faults, one in the valley of the Duddon about Duddon 
Bridge, and the other a little to the west, passing along the valley of 
Hallthwaite. It is probably to the combined effects of these faults 
that the valley of the Duddon (a striking feature in this part of the 
district) is to be referred. Taking the mean direction of the river 
Duddon as indicating that of the fault (independently of minor irre- 
gularities), we observe that it ranges about N. byE., tending toa point 
a little east of Scaw Fell. 
Another enormous dislocation is seen just above Coniston Water, 
producing a horizontal displacement of about a mile. The direction 
of the fault, as determined by a line joming the extremities of the 
dislocated portions of the limestone band, passes exactly down the 
lake. It is very nearly parallel to the Duddon fault, a little to the 
east of N. by E. Several other dislocations in this neighbourhood, 
described by Professor Sedgwick, are also indicative of so many faults 
similar and parallel to the above, but not attended by any marked 
external features. 
Another fault ranges down the valley of Troutbeck, as indicated 
by a dislocation of the limestone band and a great horizontal displace- 
ment. It ranges accurately with that part of the lake of Winander- 
mere which lies south of the embouchure of the valley. An enormous 
dislocation is also described by Professor Sedgwick between Coniston 
and Winandermere, by which the limestone band on its eastern side 
has been apparently moved towards the north to the distance of a 
mile anda half. It is not m this instance again indicated by the 
external configuration of the district, but there is doubtless here also 
a great fault parallel to those already described. On the east of 
Troutbeck also there are dislocations which cannot be doubted to 
have been connected with the formation of the two striking valleys of 
-Troutbeck and Kentmere. The line of dislocation would seem to 
pass exactly along that part of the latter valley in which the mere is 
situated. 
We have further evidence of a line of dislocation along the valley 
* The reader is here requested to bear in mind that a period of more than five 
years has elapsed since the reading of this paper to the present time, December 
1847. The late researches of Prof. E. Forbes in the #gean Sea and on our own 
coasts have completely established the argument in the text. 
