128 
THE GEOLOGIST. 
throws some doubt whether the flint-drift of our section may not 
have been brought down by landslips such as are now common at 
the Cape, and have been a portion of a former underclifT since cut 
into by the action of the sea. No fragments of shells, sand, or rock, 
indicating any amount of regeneration, are to be found in the " flint- 
drift," which consists entirely of ferruginous sand and angular pieces 
of flints, and which so far seems, allowing for local diff'erences of 
mineralogical character, to be identical with the flint-drift so exten- 
sively distributed over this region. The next question to be deter- 
mined, is how far back in geological history the species of shells 
found in the subjacent sand can be found to date their existence, be- 
cause certainly the age of this shell-sand has to be mainly determined 
by its organisms, there being but little concurrent evidence as yet ob- 
tained from other sources than the mollusca found in the' sand. The 
following are placed by Professor Forbes in his list of " species now 
living in British seas and found fossil in true glacial heds:''—Mactra 
soUda, Tellina solidula, Cardium edule, JVucula tenuis, Littorina lit- 
torea ; and Mactra stultorum is placed by the same author among 
the British species not found fossil in typical glacial beds, but occur- 
ring in contemporaneous Italian newer Pliocene strata. 
The evidence therefore of the shells brings the age of this Havre 
sand between two limits, that of the Pleistocene on the one hand, 
and the Eecent or Actual period on the other. The flint-drift, being 
superincumbent, must consequently take its place at a more recent 
stage than the sand within the same interval, if it be truly in situ. 
The fossils of the recent shell-sand are well preserved, although 
extremely brittle, traces of colour being frequent, and the specimens 
of periwinkles, though not numerous, are hard, and but little changed 
in structure, excepting by the loss of albuminous matter. The por- 
tion of a tooth of Elephas 'primigenius, found on the shore in a mass 
of hardened sandy material near the termination of the valley of St. 
Addresse, and preserved in the cabinet of M. Flambard, indicates the 
existence and proximity of some Pleistocene deposit, the discovery 
of which would possibly throw much light on the position in time 
that our recent shell-sand ought to occupy. It would be highly in- 
teresting to determine the occurrence, and trace the connection of a 
freshwater marl or other deposit, containing bones of the Pleistocene 
mammalia, in this neighbourhood. In the drift exposed in the Cape 
cliff'-section, there are evident signs of rude inclined stratification on 
the sides of the hollows and shorter sand-pipes of the chalk, and 
