GRINDLEY — GEOLOGY Or THE ISLE OE MAJf. 



173 



"witii a few fishing-boats, or darkened, perhaps, by the smoke of some 

 passing steamer. Behind this long line of wild and picturesque 

 coast rise the mountains of the great central range, occasional breaks 

 in the tall coastline, as at Laxey, permitting us to see at a glance 

 their vast proportions from their very bases to their cloud-capped 

 summits. Far away in the north we can discern the sharp-peaked 

 Barrule, and close to it the rounded head of the giant Snafield, appear- 

 ing and disappearing as the wind drives the silvery mist across its 

 grassy sides. Nearer still, we may mark the successive peaks of 

 Bein-y-Phot, Grarrachan, and Greebah. Directly in our front rises 

 the pointed head of South Barrule, while in the south the range is 

 continued through the sharp outlines of Irey-na-Lhaa, and the long 

 swelling ridges of the Mull Hills to the Calf itself. We gaze long 

 and earnestly on the glorious combination of the sublime and beauti- 

 ful before us ; but we rapidly close in with the shore — the dark cliffs 

 tower higher above our heads, and cast a broader shadow over the 

 clear green waves ; and suddenly rounding the southern corner of 

 the bay, we fire a gun, which is responded to from the shore, and al- 

 most at once we are in the midst of the throng and bustle of a fashion- 

 able watering-place. 



The general axis of the island is from JN.E. to S.W. : M'ithin 

 this line rise the highest peaks of the mountain-range, and along its 

 sides lie the upturned edges of the Manx rocks. At tw o points in 

 this central axis the granite appears at the surface, probably in con- 

 sequence of the overlying rocks having suff"ered extensive denudation 

 — near the head of the Dhoon river, about half-way between Laxey 

 and Eamsey, and on the eastern side of South Barrule. Between 

 the granites of these two localities there is an essential difference, 

 the Dhoon granite being a syenite, and of a much finer and firmer 

 texture than that of Barrule. The granite of the latter locality is 

 extensively quarried for economical purposes. 



Eesting upon the granite is a series of slaty rocks, which, as we 

 recede from the central axis, passes regularly through the successive 

 stages of mica-schist, clay-slate, and grauwacke-slate. Respecting 

 the exact geological age of these rocks it is extremely difilcult to 

 speak, the few organisms hitherto found in them consisting chiefly of 

 some imperfectly-preserved fucoids and corals — very uncertain guides. 

 Still, taking into account the character of the lower portion of the 

 series, which is undoubtedly metamorphic, and the regular passage 

 into the upper and fossiliferous portion — and, further, from a compa- 

 rison of the few fossils which have been found in this upper portion 

 with those of other localities — it seems to be now admitted that the 

 upper portion of these rocks is to be regarded as Lower Cambrian. 

 One of the best-preserved of these organisms, obtained from the 

 rocks of Douglas, and now in my own collection, has been lately 

 identified by an eminent palaeontologist as generically the same with 

 an unnamed fucoid from the Cambrians of North Wales. These 

 schists attain an enormous vertical development, probably not less, 

 than from 7000 to 10,000 feet. Their superficial development is also. 



