THE ESSEX FIELD CLUB. 187
the name of Calcrete. Mr. A. E. Salter, D.Sc., who kindly reported
upon a specimen which had been sent to him from this pit, states that
this calcrete is of not-infrequent occurrence in N.E. Herts (e.g., around
Bishops Stortford). It seems, however, not to have been observed
previously near Saffron Walden in such a well-developed form, although a
hardened layer of chalky gravel and clay (locally termed the "Manchester Bed") is
often met with just above the Chalk on the slopes of the Walden Valley.
The general physiography of the district was then briefly commented upon.
The surface of the country slopes up gradually from the S.E. to the N.W, border
of the county, where it breaks away, in the fairly-steep slopes of the Chalk
escarpment, down to the fen basin of Cambridgeshire. The chalk is exposed on
the slopes around Saffron Walden, but the hill-crests are capped with outliers of
Glacial Clay, which, to the S.E. of the town, forms a continuous sheet over the
high ground. The evidence of local well-borings shows that this clay is over 60
feet in thickness, and is underlain by a considerable depth of glacial sands and
gravels. The present drainage of the district is N. W. into the Cam ; and the
contours of the valley indicate that it must have been once occupied by a much
more considerable stream than the mere rivulet which now flows through it.
Between Littlebury and Chesterford, the stream escapes through the chalk
range. At the former place, where the valley is contracted, well-borings
prove the existence of a great trough or gorge in the Chalk below the present
valley, which is now filled with "Drift." Here borings pass through masses of
gravel, sand, and clay to a depth of 62 feet below present sea-level, and 218 feet
from the surface, while the bottom of the bore was still in Drift. The Chalk,
however, comes to the surface at 125 yards from this boring, thus showing that
the sides of the old channel were of considerable steepness. Other borings along
the line of the present valley as far as Quendon also prove the existence of this
buried channel. The whole evidence may, perhaps, be taken to show that there
have been considerable variations in the elevation of the district. These buried
channels could only have been excavated by river-action at a time when the
whole area stood much higher above sea-level than at present. Possibly they
may have been deepened by glacial ice, and then gradually filled up, either as a
further result of glacial conditions or by the checking of the river's transporting
capacity as the district gradually sank during the post-glacial period. Sections
exposed by the G.E.R. cuttings near Audley End station showed two layers of
Boulder Clay separated by a considerable thickness of gravels and sand. See
Geological Survey Memoir, No. 47 (N.W. Essex).
The party then proceeded to the Abbey Farm, Audley End, where a halt of
a few minutes was made to inspect this most charming and picturesque old
Tudor building. The brickwork has the general features of early 16th century
work, although there seems little doubt that the institution was founded in
1400 as a hospital or infirmary attached to the Abbey of St. James of Walden.
The plan was rectangular, enclosing two courts, separated by a central
wing containing the chapel and hall.
The mansion of Audley End was next visited, by kind permission of Lord
Howard de Walden. It was pointed out that the present mansion was but the
central core of a much larger structure, erected between 1603 and 1613, near to
the site of the destroyed Abbey of Walden, which had been granted by
Henry VIII. to Lord-Chancellor Audley, In the Great Hall, a noble apartment
(the chief features of which are a ceiling panelled with heraldic badges in