400 



NA TURE 



\_Angnst 26, 1880 



A FRAGMENT OF PRIMEVAL EUROPE 

 VyHEN the history of the growth of the European 

 * ' area is traced backward through successive geo- 

 logical periods, it brings before us a remarkable per- 

 sistence of land towards the north. The stratified 

 formations bear a generally concurrent testimony to 

 the existence of a northern source whence much of 

 their sediment M'as derived, even from very early geo- 

 logical times. In their piles of consolidated gravel, sand. 

 and mud, their unconformabilities and their buried coast- 

 lines, they tell of some boreal land which, continually 

 suffering denudation, but doubtless at intervals restored 

 and augmented by upheaval, has gradually extended over 

 the whole of the present European area. The chronicles 

 of this most interesting history are at best imperlcct, 

 and have hitherto been only partially deciphered. They 

 naturally assume an increasingly fragmentary and obscure 

 character in proportion to their antiquit)'. Nevertheless 

 traces can stiU be detected of the shores against which 

 the oldest known sedimentary accumulations were piled. 

 The shores have of course been deeply buried under the 

 deposits of subsequent ages. But the whirligig of time 

 has once more brought them up to the light of day b\- 

 stripping off the thick piles of rock beneath which they 

 have lain preserved during so vast a cycle of geological re- 

 volutions. I shall here describe a fragment of this earliest 

 land, and allude to some of the geological problems which 

 it suggests. 



In the north-west of Scotland, along the seaboard of 

 the counties of Ross and Sutherland, a peculiar type of 

 scenery presents itself, which reappears nowhere else on 

 the mainland. Whether the traveller approaches the 

 region from the sea or from the land, he can hardly fail 

 to be struck by this peculiarity, even though he may have 

 no specially geological eye for the discrimination of rock- 

 structures. Seen from the westward or Atlantic side, 

 as, for example, when sailing into Loch Torridon, or 

 passing the mouths of the western fjords of Sutherland- 

 shire, the land rises out of the water in a succession of 

 bare rounded domes of rock, crowding one behind and 

 above another, as far as the eye can reach. Not a tree 

 or bush casts a shadow over these folds of barren rock. 

 It might at first be supposed that even heather had been 

 imable to find a foothold on them. Grey, rugged, and 

 verdureless, they look as if they had but recently been 

 thrust up from beneath the waves, and as if the kindly 

 hand of nature had not yet had time to clothe them with 

 her livery of green. Strange however as this scenery 

 appears when viewed from a distance, it becomes even 

 stranger when we enter into it, and more especially when 

 we climb one of its more prominent heights and look 

 down upon many square miles of its extent. The whole 

 landscape is one of smoothed and rounded bosses and 

 ridges of bare rock, which, uniting and then separating, 

 inclose innumerable little tarns (Fig. i). There are no 

 definite lines of hill and valley ; the country consists, in 

 fact, of a seemingly inextricable labyrinth of hills and 

 valleys, which, on the whole, do not ri'se much above, nor 

 sink much below, a general average level. Over this ex- 

 panse, with all its bareness and sterility, there is a singular 

 absence of peaks or crags of any kind. The domes and 

 ridges present everywhere a rounded, flowing outline, 

 though here and there their outline has been partially 

 defaced by the action of the weather. 



The rocks that have assumed this external contour are 

 the Fundamental, Lewisian, or Laurentian gneiss, which, 

 as Murchison first showed, form the platform whereon the 

 rest of the stratified rocks of Britain lie. They do not, 

 however, cover the whole surface of these north-western 

 tracts. On the contrary, they form a broken fringe from 

 Cape Wrath to the Island of Raasay, coming out boldly 

 to the Atlantic in the northern half of its course, but 

 throughout the southern portion retiring chiefly towards 



the heads of the bays and sea-lochs, and even extending 

 inland to the head of Loch Maree. The reason of this 

 want of continuity is to be found in the spread of 

 later tormations over the gneiss. At the base of these 

 overlying deposits comes a mass of dark red sandstone 

 and conglomerate (classed as Cambrian by Murchison 

 and his associates), which, in gently inclined or horizontal 

 strata, sweeps across the platform of gneiss, rising here 

 and there into solitary cones or groups of cones fully 

 3,400 feet above the sea. No contrast in Highland 

 scenery is more abrupt and impressive than that between 

 the ground occupied by the old gneiss and that covered 

 by this overlying sandstone group. So sharp is the line 

 of demarcation between the two tracts that it can be 

 accurately followed by the eye even at a distance of 

 several miles. Where the sandstone supervenes, the 

 tumbled sea of bare grey gneiss is succeeded by smooth 

 heathy slopes, through which the flat or gently-inclined 

 parallel edges of the beds protrude in successive lines 

 of terrace. As the ground rises into conical mountains, 

 the covering of heather grows more and more scant, but 

 the same terraced bars of rock continue to rise even to 

 the summits, so that these vast solitary cones, standing 

 apart on their platform of gneiss, have rather the aspect 

 of rudely symmetrical pyramids than the free, bold sweep 

 of crag and slope so characteristic of other Scottish 

 mountains. 



The depth of these sandstones must amount to several 

 thousand feet. Even in single mountains a thickness of 

 more than three thousand four hundred feet can be taken 

 in at a glance of the eye from base to summit. Yet when 

 this massive formation is followed along the belt of 

 country in which it lies it is found to thin out rapidly and 

 even for some distance to disappear. Such a disappear- 

 ance might arise either because the formation was not 

 continuously deposited or because it was unequally worn 

 down before the next formation was accumulated upon it. 

 Evidently the solution of this question will have an 

 important bearing on any reconstruction of the early 

 geography of the region. 



Above the red sandstones and creeping across them 

 transgressively lies the deep pile of white quartzites, 

 limestones, and schists which Peach's discovery of 

 recognisable fossils in them at Durness showed to be of 

 Lower Silurian age. Another well-marked contrast of 

 scenery is presented where these rocks abut upon those 

 just described. The cjuartzites rise into long lines of bare 

 white hills which, as the rock breaks up under the influ- 

 ence of the weather, are apt to be buried under their own 

 debris even up to the summits. Here and there outlying 

 patches of the white rock may be seen gleaming along the 

 crests of the dark sandstone mountains like fields of snow 

 or nascent glaciers. Quartzites, limestones, and schists 

 dip away to the east and pass under the vast series of 

 younger schists which form most of the rest of the Scottish 

 Highlands. This order of succession, first established by 

 Murchison, can be demonstrated by innumerable lines of 

 natural section. I have myself traced it through the 

 mountainous country from Cape Wrath to Skye, and in 

 many traverses across Sutherland and Ross. I have 

 sought for evidence of the reappearance of the old or 

 fundamental gneiss of the north-west, and have ransacked 

 every Highland county in the search, but have never 

 found the least trace of that rock beyond its limits in 

 Sutherland and Ross. Its distinctive gneisses and other 

 crystalline masses, so wonderfully unlike anything else in 

 the Highlands, never reappear to the east. And that 

 strange mammillated, bossy surface is found in the north- 

 west alone. 



To realise what the appearance of the old gneiss at the 

 present surface means we must bear in mind that it was 

 first buried under several thousand feet of red sandstone, 

 that the area was then further submerged until the vast 

 pile of sediment was deposited out of which the High- 



