30 THE ESSEX NATURALIST
The pit is now worked out and flooded, so that it can be
known only by the original descriptions and by stored collec-
tions. The writer was with the Geologists' Association when
they visited the site in 1946 [Geol. Assoc. Circular No. 495],
and his collection has been augmented by some material kindly
supplied by Mr. Warren. Plate 4 and Table 1 summarise
the sequence of events as interpreted by the latter at Nazeing
itself but do not take into consideration any discoveries in other
parts of the valley.
Attention should be drawn to two main sequences of events,
the one taking place in what Warren calls the 'temporary mere,'
represented by "Bed D" and the other in a channel cut deeply
through the "D" beds. The filling of this channel included
some charophyte marls and muds rich in organic matter,
deposits designated the "M" beds.
Before describing the occurrences of the Nazeing Stage in
the new localities it will be well to repeat, with annotations,
the sequence recorded in what may be regarded as the type
sections of these beds. That selected for Bed D was at Site X,
near but outside the M channel. Its position is given in the
map on page 171 of the Nazeing paper, and the sequence is on
page 195. The latter, with some modifications authorized by
Mr. Warren, is reproduced below :—
The Type Section of Bed D,
7. 30 cm. MARSH CLAY.
6. 10 cm. Transition.
5. 75 cm. BOREAL AND ATLANTIC PEATS. Black
fen-wood peat with oak and alder, rhizomes, of
hedge, and with hazel nuts locally near the base.
4. Discontinuity—"SURFACE D".
3. 15 cm. SOIL LAYER. Black clayey mud with wood
fragments and Equisetum palustre.
2. 65 cm. MARL D. Pale yellowish brown calcareous
lake marl. Freshwater and land molluscs
abundant in patches.
1. 5 cm. PEAT C. Black greasy homogeneous mud,
non-calcareous.