A NEOLITHIC FLOOR.
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flints or "pot-boilers," while occasionally patches of red-burnt
earth occurred at various levels in the peat, marking the spots
where fires had been lighted at different times while the peat was
forming. We also found some fragments of rude hand-made
pottery, similar to that which Mr. Rand had previously obtained
from the site, and there were many animal bones.
All these indications formed abundant evidence of the peat
having originally been a land surface out of reach of the tides,
and one on which some band of early men had settled, making
flint implements and cooking their food.
Unlikely as such a spot may seem for the occupation of man
under the conditions at present prevailing, it is evident that this
deposit now buried under at least six feet of tidal mud was once
the surface, unwashed by salt-water, on which man was living
in comparatively large numbers.
Overlaying this bed of peat is about three feet of tidal clay,
when another band of peat-growth is visible. Again, this must
have formed a later surface untouched by the tides, succeeding
a considerable period of gradual submergence during which
the three feet of tidal silt was deposited. This upper band of
peat was only three or four inches in thickness and, so far, no
relics have been discovered in it to give any clue to the age of
its formation. Over this higher peat several feet more of clay
mud has accumulated and forms the salting surface which exists
to-day.
These phenomena represent breaks in the general downward
earth movement during the time the most recent alluvium of
the river has been accumulating.
If, as appears, judging superficially, the lower peat rests on
tidal silt, we must conclude that the river of this part was estuarine
before the formation of the lower peat. Such alternate deposits
of tidal silt and peat would suggest subsidence followed by
emergence, this process being repeated to form the upper
peat, and being in turn succeeded by subsidence to the present
condition of things.
Similar layers of peat are found in the recent alluvium of
the Thames, and have also occurred in many of the East Anglian
rivers. Some of these are probably the result of special and
local causes, such as the shifting of the stream in its bed, or
some temporary obstruction such as fallen trees swept together
R