124 Rev. A. Irving—Outliers on North Downs. 
date) are the exact counterpart in every way of the Upper Bagshot 
Sands, as these are seen in the interior of the district ; e.g. about 
Sandhurst, in the Fox Hills, and at Aldershot. Of those at Headley 
I should speak with more reserve as to their being Upper Bagshot, 
although I saw no good grounds for denying that they might repre- 
sent the more marginal facies of the beds of that group. There is 
rather more distinctness of bedding than usual, and the sands are 
rather less loamy, and more marked by colour-bands, as the result 
of subsequent infiltration. But this can be observed even in the 
highest beds of the Fox Hills in places, and elsewhere in the 
district. 
Associated with these sands on the Chalk hills at Headley, and in 
the debris of the hill-slope, well-rounded flint pebbles are met with 
in great numbers; at Headley they constitute a large proportion of 
the drift-gravel, which overlies the sands. These pebbles are so 
different from those which occur in the clays on the Downs, and so 
closely resemble the bluish Bagshot pebbles of Bearwood, Hast- 
hampstead, St. Anne’s Hill, Chertsey, Aldershot, etc., that it seems 
impossible to deny that they may belong to the same formation. 
Sarsens also are not infrequently met with. 
So far as the evidence goes, we seem (though it is not very strong) 
to have better grounds for assigning these outlying sands to the 
Bagshot (and perhaps to the Upper Bagshot), than any which has 
yet been brought forward for assigning them on the one hand to 
the Reading Beds, and on the other to the Pliocene.’ 
Assuming that they are of Bagshot age, and taking their present 
altitudes (550 to 600 feet above O.D.) into account, we arrive at the 
interesting and important result, that this represents approximately 
the extent of the post-Hocene elevation of the North Downs above 
the sea; and the differences between these and the present altitudes 
of the same horizons in the interior of the Bagshot area (if they 
could be precisely identified) would represent the extent of 
accentuation which the Wealden axis has undergone since the 
ocene period. 
The extensive prevalence of the Reading Beds to the south points 
to a later date for the elevation of the Wealden axis than that 
marked by those beds; while the presence of the pebbles in great 
force seems to indicate that the Chalk over the Wealden area was 
subjected to the abrading action of the sea to a large extent before 
the Hocene period” came to an end (as is well known) ; and to such 
an extent was this carried on, that even the Lower Greensand was 
exposed to the action of denuding agencies, and furnished a great 
part of the materials of the Upper Bagshot, in which scattered 
glauconitic grains occur locally. 
1 See Mem. Geol. Survey, vol. iv. 
® Exclusive of the Oligocene. 
