64 Proceedings of the Royal Physical Society. 
whose sides—at least the western one — decline very 
gradually.” 
Now again, in endeavouring to supplement our previous 
summary, and bring our information concerning Rockall up 
to date, we desire it to be understood that we do not claim 
this far-off fragment of the earth as a part or portion 
belonging to the faunal area of the Outer Hebrides, because 
certain facts which have become known to us since the date 
of our last article upon it, tend to the indication of its 
geological and faunal relations to the islands of Iceland, or 
at all events to more recent volcanic action than we have 
any traces of in the Hebrides; and the soundings show, 
probably, much more decided rupture or separation from 
any of our British isles than from more northern land. 
Soundings, when more exhaustively overtaken, may, and 
doubtless will, assist us further in our judgments in this 
direction ; and before long, as we have some reason to hope, 
such soundings, and a more minute account of the rock and 
its surroundings, will be attempted, and more definite infor- 
mation obtained regarding its geology, flora (if any), and 
fauna. 
In Basil Hall’s account, the geology of the rock has been 
described as a “ dark-coloured granite,” and this has been 
repeated in the corner of Captain Vidal’s map, where the 
stone is spoken of as “ coarse granite.” 
From what has already been published regarding this still 
somewhat mysterious ocean-rock, we know a few points of its 
history. We know its position with considerable accuracy ; 
and the Admiralty chart, which is now out of print and 
scarce, has laid down upon it accurate soundings so far as 
the survey was mapped. We know that it is surrounded by 
dangerous reefs, especially those which le out three-quarters 
of a mile or thereby towards the N.E. The fishing banks 
around, as is well known to crews and masters of fishing 
smacks from Grimsby, Fverde, and Shetland, lie at depths of 
from 60 to 120 fathoms. We know also that it is a nursery 
for sea-fowl, and positively that a species of guillemot breeds 
upon it, besides several other birds, of the identity of some 
of which, however, we are not so certain. | 
