131 
THE BOSCOMBE SANDS (LOWER BRACKLESHAM). 
These form the lowest beds of the Braeklesham Series in our 
district, according to Mr. Gardner’s division, or, if the arrange¬ 
ment of the Geological Survey is accepted as described by Mr. 
Clement Reid, the Bournemouth Marine Beds, upon which lie 
the Boscombe Sands, are regarded as being the lowest of the 
Braeklesham. They commence in the upper part of the cliffs, 
near Bournemouth Pier, (Plate XV., Fig. i), and gradually 
increasing in thickness, form the mass of the cliff beneath 
the Plateau gravel, lying upon the Bournemouth Marine Beds as 
far as Southbourne, where the latter dip beneath the beach. Owing 
to the easterly dip of all strata—except the Plateau gravel—they 
increase in thickness throughout the section as the lower beds 
descend to the beach level. Thinning out westward, near Bourne¬ 
mouth Pier, their thickness increases to 50ft. at the highest point 
of the cliff eastward, before Boscombe Chine is reached. 
These Braeklesham beds consist of irregularly stratified layers 
of white and yellow sands, interspersed with shingle beds of well 
rolled flints, which have been derived from the chalk. The flint 
pebbles are mostly small, but a few larger ones occur, chiefly east 
of Boscombe Pier. They are “ battered,” that is, they bear 
concussion marks, caused by their having been dashed about by 
wave action on a sea beach. In this they differ from the flints 
from the Plateau gravel which covers them, the latter showing 
no ,such marks. The Braeklesham pebbles are faintly patinated 
white or grey in contrast to the deep ochreous flints of the gravel. 
There is, however, some 300 yards east of Boscombe Pier, a patch 
of flints having 1 a bright yellow patination, but this is purely 
local. Many small black or brown pebbles, derived from Woolwich 
and Reading Beds also occur. Lastly, the completely rounded or 
oval form characterizing the Boscombe Sand flints is persistent 
and significant. 
\ he distribution of sand and flints is very irregular, and affords 
evidence of their having been frequently moved and redeposited by 
wave action. The pebbles sometimes occur in layers, resembling 
shingle beds, at other places in thick, continuous masses.. The 
sand grains are dull yellow or brown, consisting of partly rounded 
or sub-angular quartz particles, stained with limonite in the 
darker varieties. The whiter sands frequently occur in pockets 
and sometimes are of great purity, forming an exceptionally 
perfect glass-sand. The sands have no cohesion and readily 
blow away from the cliff face. Mr. Gardner observed that the sand 
pockets were frequently lenticular in section, and suggested that 
they indicated cross sections of ancient channels parallel with the 
old shore.* The darker sand is sometimes feebly cemented in 
irregular bands, resembling current bedding, by traces of 
limonite, but can nearly always be crumbled by the hand. A rare 
* 
Q.J.G.S., 1879, vol. xxxv., p. 219. 
