Rev. A. Irving—Outlers on North Downs. 123 
surfaces scratched and polished. As the movement is greater than 
the possible velocity of glaciers, it is only natural to expect great 
erosive effects from stones held as graving tools, or wrenched out 
owing to the brittleness of the ice, under such great stress, or 
from loose materials roughly thrust forward by the pack. 
12. These observations and those of Prof. Milne’ in Newfound- 
land, and others upon the action of coast-ice, all confirm the cor- 
rectness of the verdict given by many geologists, especially in 
Hurope, who have had the opportunity of studying living glaciers, 
viz. that the potency of land-glaciers as great eroding geological 
agents is not proven, if indeed they operate at all in such a manner. 
IX.—Tertrary Ouriters on THE Nortu Downs. 
By the Rey. A. Irvine, B.Sc. (Lond.), B.A., F.G.S. 
i “Nature,” August 26, 1886, vol. xxxiv. p. 387, I ventured to 
draw a distinction between the outliers of unfossiliferous 
Tertiary sands found at high altitudes on the North Downs and the 
deposits containing casts of fossils of Pliocene age which are found 
in hollows in the Chalk at Lenham. Last summer I visited and 
examined, I believe, all the more important outliers of the former 
series, Mr. J. Hutchins French, F.G.S., having kindly conducted 
me to those at Headley and Chipstead; those at Netley were visited 
with other members of the Geologists’ Association under the direction 
of the same gentleman. The conclusion at which I have arrived 
from the lithological evidence (and there seems to be no other avail- 
able) is, that these sands are more probably of Bagshot age than of 
any other.’ 
There is a vast amount of reconstructed clay material capping 
these hills over many square miles, which, in colour and other 
characters, points to its original deposition as part of the Reading 
Beds, and in these unrolled Chalk flints are generally sparsely 
distributed. There are also a good many outliers of those beds 
mapped by the Survey on the higher parts of the North Downs.’ 
But there appear to be no traces of London Clay or of the Middle 
Bagshot clays. 
Of the unfossiliferous sands referred to, those exposed in the sand- 
pit in Chipstead Wood, and those seen in the pit on Netley Heath 
(where only one section occurs of undoubted Tertiary sands in siti, 
clearly differentiated from the overlying “run-of-the-hill” of later 
See Gronoctcat Macazine, Dec. Il. Vol. III. No. 7, p. 303, 1876. 
“ Nature,’ Oct. 16, 1887, vol. xxxvi. p. 531. 
Surely these are the patches of “‘clay-with-flints’’ (Argile a siler) of W. 
Whitaker and the French and Belgian geologists. —H. W.—The clays referred to 
are quite distinguishable from the ‘“ clay-with-flints’? of Mr. Whitaker and the 
Survey, if by that term is understood the insoluble residue frequently found on the 
surface of the Chalk, the calcareous constituents of the original rock having been 
dissolved away by carbonated atmospheric waters; a kind of deposit known to the 
French geologists as ‘“argile a silex”’ or ‘‘ terrain superficiel de la craie’’ (Memoir 
Les Causes Actuelles en Géologie, p. 306).—A. I. 
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