ON THE LEA VALLEY.
5
section. Elsewhere the proportions of the two would vary
extremely in the course of 20 yards or less, as in Fig. 2. Some-
times the loam towards its base became very dark and peat-like
in appearance, and its line of junction with the underlying gravel
very irregular, as in Fig. 3. Occasionally, between the gravel
and the surface loam, a thin irregular bed of shellmarl appeared,
or a definite bed of peat, formed of the remains of water or
marsh plants, as in Fig. 4. Again, at about the level of a bed
of peat of the kind just mentioned, formed of the remains of
plants which had grown and decayed where the peat is now seen,
tree and plant remains which had been deposited under totally
different circumstances were occasionally visible in irregular
bands towards the top of the gravel, as in Fig. 5.
The shell marl was usually in thin, irregular, lenticular
bands, seldom exceeding 1ft. 6in. anywhere in thickness, and
Fig. 2. New Reservoirs, Walthamstow. Height of Section about 9 ft.,
length about 50 yds.
disappearing in the course of 20 or 30 yards, as in Fig. 4. But
at one spot near the outfall of the Ching the section consisted of
The shells were those usually making up the shell marl.
At another spot the beds were—
At a third place was seen—
In this case the shell marl retained the above thickness for
a horizontal space of about 3ft., the whole band disappearing in
less than twenty yards.