THE ESSEX FIELD CLUB. 117
belt Of the characteristic Oak-Ash woodland was then examined. The
principal features of this were the absence of the Oxlip (Primula elatior),
which is so marked a feature of the woodland on the east of the Cam,
and the characteristic associations of Carex pendula and Aira. Attention
was also called to the great abundance of the bramble Rubus coesius,
and th? absence of Rubus fruticosus was commented upon.
Leaving the wood, the party passed across the clay waste where the
different plant associations were examined.
(1) The open flora of the most barren parts with Taraxacum dens
leonis, Fragaria vesca and Hypericum hirsutum, dominants.
(2) The Lotus corniculatus association on slightly richer soil.
(3) The invasion belts of Brachypodium, Rubus, etc., from the
woodlands.
(4) The damp hollow associations of Centaurea nigra and Arrhena-
therum elatus which culminate in a ditch zone of Spiraea ulmaria.
During a short rest, Mr. L. F. Newman, of the School of Agriculture,
Cambridge University, gave an address on the chemistry and physical
character of the local soils from the agriculturist's standpoint, dwelling
on the great importance of the size of the soil particles upon plant life.
He pointed out that the extreme fineness of the clay particles was the chief
reason for the difficult nature of the boulder clay. In dry weather the
particles were baked together into a hard crust, which effectually kept
out light and air and prevented plant development.
Crossing the waste, specimens of Blackstonia perfoliata, Hieracium
pilosella and Centaurium umbellatum and other chalk-flowers were gathered.
On the top of hill specimens of the Bee and Spotted Orchids and Tway-
blade were found, while in a belt of woodland to the north specimens of
the Bird's-nest and Butterfly orchids were seen. In this wood the char-
acteristic Melampyrum cristatum occurs and also a few plants of Bracken,
which is rare in this district.
Leaving the wood, the party then passed through a waste area of con-
siderable age which had reverted to White-thorn scrub. Here many
Bee Orchids were seen.
Lower down the hill the presence of Helianthemum was noted,
showing the presence of the chalk outcrop.
Later in the day Lamium galeobdolon was obtained in a wood behind
Chrishall Church.
At one point the highest land of the county was crossed, the elevation
being just under 500 feet above sea-level, and eventually the excursionists
made their way to the brakes at Bilden End.
Chrishall Church was visited and the fine canopied brass to Sir John
de la Pole and lady, 1370 A.D., and other monuments were inspected, and
the party then drove through Chrishall and Elmdon, glorious views over
Cambridgeshire and the Fen Country being obtained from the high ground.
At Elmdon Bury, tea had been provided on the lawn by Mr. J. F. Wilkes,
after which a short visit was paid to the ancient entrenchment from which
the property takes its name, and to the church. Hearty votes of thanks
were passed to Mr. and Miss Wilkes for their hospitality, and the great
interest they had taken in the day's proceedings, and the company then