GllINDLEY — GEOLOGT OF THE ISLE OE MAN. 
181 
Another excellent locality for the study of these arches and caves, 
is the coast about the mouth of the Santon's Burn, two miles N.E. of 
Castletown. As at Langness, the strata are much disturbed by the 
intrusions of greenstone, and, in consequence, several magnificent 
arches and a number of moderately-sized caves have been hollowed 
out in the rocks. Some interesting specimens may also be found at 
Port Soderic, a small inlet of great beauty about four miles south of 
Douglas ; at Spanish Head and the Calf, where are some splendid 
grottos, and where the remarkable one called the "Eye" deserves 
particular notice ; also at Peel, where many smail but interesting 
caves have been scooped out of the Old P-ed conglomerate. 
The organic remains found in these deposits are of the usual 
character. In the Boulder-clay, fragments of the bones of cetaceans, 
etc., have been found ; and in the clays and sands, shells belongiiig 
to existing species are found in great abundance, " the most frequent 
species being Tellina solidula, Venus cassina, Astarte Scotica, and 
Tarritella terehra''' 
The phenomena of the Drift period may be well studied in the 
great valley which crosses the middle of the island, between Douglas 
and Peel, and in most of the side-valleys communicating with it, par- 
ticularly Spring valley and the valley of West Baldwin ; also in the 
flat districts of the north, and in many of the valleys of the south. 
In some of these localities, and especially in various parts of the 
great central valley, the successive elevations of the post-glacial sea- 
bottom may be very distinctly traced, until, in very recent times, it 
assumed its present level. In very recent times, geologically, the 
sea entered this valley at both its extremities, and it was drained 
finally by an alteration of the sea-level, which was probably the last 
that affected to any great extent the physical condition of the island ; 
an event which seems to have taken place within the traditional age, 
if the name of the former residence of the Duke of Athol — Port-e- 
chee, the haven of peace — or the assertion of the inhabitants of Dou- 
glas, that the land is even now gaining upon the sea, may be received 
as evidence. On the low alluvial land laid bare at the mouth of the 
Douglas by this latest alteration of sea-level, the old tow n of Douglas 
is built, and the inhabitants state that within memory the sea has 
retired a considerable distance, and that houses which, when built, 
were close to high-water mark, are now at some distance from it. So 
small was this uprise, and so inconsiderable is the elevation of this 
valley above the existing sea-level, that a very slight depression of the 
land would again cover it with the waters of the sea, and again divide 
the island into two or more portions. This valley is drained on its 
eastern declivity by the Douglas, and on its western by the Neb, both 
of which rise close beside each other near St. John's, and so incon- 
siderable is the height of their sources, that the cutting away of a 
foot or two of turf in this spot, would cause the Neb to flow eastward 
to Douglas, or make the Douglas flow westward to Peel. 
In connection with these oscillations of sea-level, we may also 
notice the fact, that in the south of the island, near Strandhall, be- 
