GRINDLET — GEOLOGY OE 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 small but interesting 

 caves have been scooped out of the Old Eed 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 belonging 

 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 vallej^s 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 aff'ected 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 town of Douglas 

 is built, and the inhabitants state that within memory the sea has 

 retired a considerable distance, and that houses which, w^hen 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- 



