1846.] MURCHISOT« ON THE SCANDINAVIAN DRIFT. 375 



ritime cliffs, such falls of angular masses of rock are not unfrequent. 

 In numerous spots, indeed, the blocks of sandstone, though completely 

 disjointed and widely separated, conform on the whole to a horizon- 

 tal arrangement, and it was only at very rare intervals that we could 

 detect the subjacent horizontal parent rock from which they had 

 been dislocated*. 



Whatever may be the cause assigned for the production of this 

 chaos in situ, there can be no sort of doubt that the same agent 

 has operated over several degrees of latitude in Sweden, effect- 

 ing exactly similar results on innumerable low ridges of hard rock, 

 whether they be composed of granite, of gneiss, of quartz rock, 

 of porphyry, or of finely laminated sandstone. If therefore some 

 authors have been disposed to attribute the abruptly broken frag- 

 ments of certain granites, as well as their degraded surfaces f, to the 

 mere action of the atmosphere and concentric exfoliation, how can 

 they contend that such an agent can also have produced the same 

 appearances in stratified sandstones ? How, in a word, can atmo- 

 spheric agency, which, if it did anything, would only round off the 

 edges of hard sandstone, have piled up these masses in every gro- 

 tesque attitude on each other, at all angles of inclination in refer- 

 ence to their original bedding, and even sometimes in vertical po- 

 sitions? The observation of such phsenomena in a low and slightly 

 undulating region, remote from high mountains, is important as en- 

 abling us to discard any partial views founded on the exfoliation of 

 certain granitic rocks, and compels us to seek for some powerful 

 mechanical agency by which the chaotic arrangement of enormous 

 blocks apparently in situ has been produced in such situations. 

 Before we consider this question, which leads to one of the ge- 

 neral conclusions with which this memoir will be terminated, I 

 may say, that most of these blocks consist of finely laminated and 

 slightly micaceous hard sandstone, and that many of these split into 

 large flagstones of variegated colours, and with spots and ripple- 

 mark surfaces, while others are more indurated, thick-bedded and 

 quartzose, splitting under the hammer rather with a conciioidal than 

 a laminated fracture. As a whole, however, they so evidently be- 

 long to one original mass extending over an area of many square 

 miles, that independently of the existence of horizontal sandstones 

 in places which are quarried in this range a little to the north, it is 

 quite clear, from this uniform structure alone, that the rocks con- 

 stitute merely one subdivision of the Old red formation of Scandi- 



* In the discussion which followed the reading of M. Durocher's mcinoir before 

 the Geological Society of France in November, and in which I took i)art, my friend 

 and companion, M. de Verneuil, stated some of the facts relating to this singular 

 tract. But the plucnomenon is too important to be parenthetically disjiosed of, 

 and requires the further explanation which I now offer. 



t I fully a(hnit that in Cornwall, and in many other granitic tracts, alnui- 

 spheric action has so affected the rocks (in the manner ably explained by Dr. 

 M^CuUoch), that the detached blocks have often the appearance of suporlifial 

 detritus. But the " tors" and granitic blocks in si/n of those countries are wholly 

 unlike the great angular and abruptly broken blocks of the tracts under con- 

 sideration. 



