The Chalk and its Dislocations. 305 
maintained by Mr. Reid in his Survey Memoir, in which he urged 
that it was the only one which would fully explain the facts 
(ad., p. 114). 
The postulate of a North Sea ice-sheet seems to me, as it has 
always seemed to me, the most stupendous unverified and unverifiable 
premise that the great adepts in such postulates, the glacialists, have 
produced. As a physical fact, and even possibility, it is absolutely 
scouted by every physicist before whom I have put it for criticism, 
and this includes some of the most distinguished in these realms; 
and it is astonishing that, in view of this hypothesis traversing very 
elementary physical laws, it should continue to be put forward by 
geologists without the smallest attempt to justify its possibility. 
Note especially Mr. Lamplugh’s extraordinary appeals to it in various 
ways down to the address he lately gave at York. 
It is not only the physicists, however, who object to this particular 
sample of professedly scientific appeals without scientific justification. 
Pettersen and other Norwegian geologists have conclusively shown 
that if there was a North Sea ice-sheet it could not have come from 
Western Norway, since it is perfectly plain from the distribution of 
the erratics that the Norwegian ice never even reached the string 
of islands that fringe the Norwegian coast. 
Such an ice-sheet, if it existed at all then, could only have been 
composed of frozen sea-water like that on ponds and lakes, and like 
that in the palocrystic sea, which does not move as a glacier 
moves. Its crystalline structure is entirely different to glacier ice, 
and it cannot be made to shear. Here, then, are some very elementary 
reasons why the North Sea ice-sheet of Glacial geologists has been 
described as a mere outcome of nursery science. 
This makes Mr. Reid’s appeal to it as an alternative to the 
Rey. O. Fisher's appeal to the pressure’ of superincumbent_ strata 
a very inconsequent one. Granting, however, the existence of such an 
ice-sheet (which I am only prepared to grant as having an imaginary 
existence in Cloudland), how does it serve Mr. Reid’s purpose ? 
He seems to think that an ice-sheet could ‘‘ exert enormous lateral 
thrust or a sliding pressure from above.” How was this to happen ? 
Nothing can be plainer, and I have adduced abundant proofs which 
have satisfied physicists in more than one of my works that such an 
ice-sheet could not move en masse over a flat or uneven surface for 
more than a very short distance. No conceivable impulse to cause 
such a movement as the theory of the North Sea ice-sheet requires is 
forthcoming which would not crush the ice into slush and dissipate 
all its energy. Any movement in such ice-sheets must have been 
molecular and not a movement en masse. How is Mr. Reid to secure 
his lateral pressure or his sliding pressure from above in a mass of ice 
moying molecularly and in which the molecules moved over each other 
at a snail’s pace? Perhaps some one who understands how the end 
could be compassed by the suggested means would explain the process 
before its possibility was so jauntilyassumed. Surely this stupendous 
premise should have been verified. 
To me it is an insoluble mystery how such hypotheses can be 
treated as science at all. Without Mr. Reid’s lateral pressure, ice 
DECADE VY.—VOL. IV.—NO. VII. 20 
