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2. Below this is a thin layer of angular gravel, one to 
two feet in thickness. 
3. Still lower is a bed of sandy marl, five to six feet thick, 
with land and fresh water shells, which though very delicate, 
are in most cases perfect. 
4. At the bottom of all, and immediately overlying the 
chalk, is the bed of subangular gravel in which the flint 
implements are found. 
In the early Christian period this spot was used as a 
cemetery : the graves generally descend into the marly 
sand, and their limits are very distinctly marked, an 
important fact, as showing that the rest of the strata have 
lain undisturbed for 1500 years. The cofhns used were 
sometimes made of hard chalk, sometimes of wood, in which 
latter case the nails and clamps only remain, every particle 
of wood having perished, without leaving even a stain 
behind. Passing down the hill towards the river, all these 
strata are seen to die out, and we find ourselves on the bare 
chalk ; but again at a lower level occurs another bed of 
gravel, resembling the first, and capped also by the bed of 
brick earth which is generally known as loess. 
These strata, therefore, are witnesses ; but of what ? Are 
they older than the valley, or the valley than they ? Are 
they the result of causes still in operation, or the offspring 
of cataclysms now, happily, at an end. If, indeed, we can 
show that the present river, somewhat swollen perhaps, 
owing to the greater extension of forests in ancient times, 
and by an alteration of climate, has excavated the present 
valley, and produced the strata above enumerated, then " the 
suggestion of an antiquity for the human family so remote as 
is here implied, in the length of ages required by the gentle 
rivers and small streams of eastern France to erode its whole 
plain to the depths at which they now flow, acquires, it must 
be confessed, a fascinating grandeur, when, by similitude of 
