74 



HARD IV I CKE ' S S CIE NCE -GOSSIP. 



immense lateral pressure emanates from the sea itself 

 tending to fold, elevate, and crush the portion of the 

 over-crust situated here. 



Geology. 



Our old familiar friend the metamorphic clay-slate 

 of the Silurian system here greets us as of yore. 

 The entire skeleton, so to speak, of the island and 

 all the highest mountains thereof are composed of it. 

 In fact, it may be regarded as the sine qua tion of the 

 territory, as doubtless a softer or a less matured or 

 worse tempered rock would have been swept away 

 long ago by the seas, or rather would not havs 

 endured the tremendous pressure from beneath and 

 laterally to which it has evidently been subjected, 

 It occurs in four forms, viz. as a sandstone or grit, a 

 grey flagstone, a black slate, and a soft black shale. 

 The Skiddaw slate of Cumberland is its nearest 

 analogue ; but the volcanic green slate and porphyry 

 of that period have not here been observed in 

 connection therewith. In places it is observed to be 

 very slaty and splintery, indeed almost shaly. Here 

 and there it is beautifully stratified, but sometimes it 

 is twisted, contorted, bent nearly double, and its 

 edges upturned (as at Little Ness and near Glen 

 Cam), so as to be almost or quite vertical. These 

 contortion phenomena are specially noticeable among 

 rocks which jut into the sea, or at the base of marine 

 precipices. Is it possible that the stupendous weight 

 and impetus of the sea-water on either side of the 

 strata may have exerted a mighty sideward pressure 

 thereon sufficient to upraise and bend them ? It is a 

 singular fact in geology that all the existing volcanoes 

 on the earth are near the sea or very large sheets of 

 water, and as earthquakes are intimately connected 

 with volcanic eruptions, it would appear that the 

 motions of the water are more concerned with the 

 folding and wrinkling of the earth's crust, etc., than 

 what is generally supposed. However that may be, 

 we must now remark that in the island we are now 

 reviewing, the old red sandstone appears next after 

 the Silurian slate resting unconformably thereon. It 

 has evidently been greatly denuded, as it now 

 appears in only a few places, such as for a mile and 

 a half along the shore to the north of Peel, and near 

 Ballasalla and Derby Haven in the south. On the 

 peninsula of Langness it is seen as a conglomerate 

 (supposed by Ward to be identical with the basement 

 conglomerate of the carboniferous formation), and 

 presents a beautiful and picturesque appearance, 

 being composed of quartzite pebbles and boulders im- 

 bedded in a limestone matrix resting on the upturned 

 edges of the slates, and chiselled by the waves into 

 numerous grottoes, arches, pillars, pinnacles, etc. 

 Next in order, and resting with complete conformity 

 on the old red or conglomerate (as is well seen at 

 Langness) come the well-known pinky-white, well- 

 stratified slabs and spreads of the carboniferous 



limestone. It surrounds the bays in the neighbour- 

 hood of Castletown ; and occurs also at Port St. 

 Mary, Ballasalla, etc. To the north of the Peel 

 there are the remains of a bed, and boulders of it are 

 frequently washed up all along the north-west coast ; 

 so that it would appear that a sort of limestone reef 

 occurs under the sea in that quarter. Its texture is 

 for the most part finely granular, being fossiliferous 

 only in a few places. At Poolvash, doubtless owing 

 to the influence of the adjacent igneous rocks, it is 

 developed into a fine, black, softish marble suitable 

 for chimney-pieces, etc. After the limestone, there 

 is a great gap or break in the succession of the Manx 

 geological strata. The great formations of the 

 Permian, Triassic, Jurassic, Cretaceous, Eocene, 

 Miocene, and Pliocene are utterly unrepresented. 

 Not a particle of coal, millstone grit, new red 

 sandstone, lias clay, greensand, chalk, etc., has been 

 found in the island. While, according to our ultra- 

 speculative geologists, England, etc., has been 

 alternately and periodically "ducking" up and 

 down for so many thousands or millions of years in 

 order to receive these deposits and their fossils, the 

 Isle of Man has either remained stationary, or the 

 stuff has all been swept off it. However that may 

 be, it is certain that the Pleistocene formation is here 

 extremely well developed, "better, perhaps," as has- 

 been said, "than in any other part of Great 

 Britain." It covers all the lower tracts, i.e. to not 

 more than five hundred feet above the sea-level, and 

 is especially prominent in the great level plain on the 

 north, and in the valley between Douglas and Peel. 

 It consists of sand, gravel, shelly clay, rounded 

 pebbles and boulders of almost every kind of rock, 

 and forms as it were a sort of connecting link 

 between the high dry land and the oozy depths of 

 old ocean. Chalk flint, bluish clay (till), shell marl 

 have also been found. Where these boulders came 

 from, is a knotty problem. Geologists prate about 

 ice and glaciers and the glacial period, and what not ; 

 but the idea of these outlying, heterogeneous masses 

 of rocks being gradually pushed up from below by 

 some lateral or other pressure, seems never to have 

 tickled their heads. It may be observed, that in 

 general there is a conspicuous absence of boulders on 

 the Manx mountain sides, and there is little or no 

 evidence of local glaciers, or indeed of ice-chiselling 

 of any kind. The volcanic rocks of the island 

 consist of "ash and breccia intersected by dykes of 

 basalt," and form some very remarkable rugged and 

 jagged pinnacles of low elevation on the southern 

 shore. 



Mineralogically considered, the island is extremely 

 interesting. The granite is the most beautiful ever 

 seen, being composed of flakes of glistening white 

 silvery mica, and of white felspar imbedded in a 

 pinky-white snowy quartz : frequently the felspar is 

 left out of the bargain, and there is nothing but 

 quartz and mica. Calcite and dolomite in very fine 



