37
some cases such explanations are not always
adequate.
PETER ALLEN
BOTANY MEETING, WARREN FARM CHALK PIT SURVEY
29TH JUNE, 1986
Tragically this magnificent pit, together
with all the other large chalk pits in the
Grays area, is threatened with development.
It has already been extensively back-filled
on the eastern margin, and in the north-
eastern corner there is an extensive scree
slope of dumped composite building blocks.
The floor of the pit is swampy and exten-
sively ridged with wide, waterlogged hollows
in between, and the whole area is densely
colonised by Goat Willow, Sallow and Osier
hybrids. A large,shallow pond in the
northern part of the pit supports a Mare's-
tail (Hippuris) colony and Ranunculus tri-
chophyllus. In the more open central area
a good variety of typical chalk species
occurs, including Yellow-wort (Blackstonia),
Centaury, Carline Thistle (Carlina vulgaris)
Ploughman's Spikenard (Inula Conyza), Bee
Orchid, and Purging Flax (Linum catharticum)
In this central area under the sallows, the
main area of Marsh Orchids occurs, with
Southern Marsh Orchid (Dactylorhiza praeter-
missa) predominating, with Common Spotted
(D. fuchsii) and their presumed ring spotted
hybrid.
The southern half of the pit floor is enclosed