New Telephone Exchange, Ipswich

194

THE BROOM HILL GRAVEL

It is now apparent that Winkworth's Pit, situated between Rushmere and Woodbridge Roads and now filled in, and the derelict pit on the right of Playford Road, Rushmere, both belong to the Creeting gravel. In the latter the pale-coloured sand was formerly exposed under the gravel below the g^neral floor of the pit. Unfortunately no erratics were collected from these pits while they were being worked.

The establishment of the relationship of the Creeting gravel to the boulder clays, which are now proved to have been laid down by separate ice sheets, a fact which has hitherto been disputed, also proves the current bedded pale-coloured sand on which it rests to belong to the Corton Beds ; at least there can be no reasonable doubt that the sand occupies the same position in the geological sequence. It only remains for marine mollusca, similar to the scanty fossil shells which have occasionally been found in the Corton Sand, to be discovered for the removal of the last possible doubt; actually a few shells were discovered some years ago in a sand pit at Stowmarket but this was not learned until after the pit was disused.

The deep trenches excavated for sewers on the new Chantry Estate at Ipswich cut into a thick deposit of pale-coloured sand but in this area there are complications arising out of the presence of decalcified Crag sand. In the Valley Farm Pit, Sproughton, a considerable thickness of pale sand passes down into typical shelly Red Crag. The bedding merges definitely from the uncoloured unfossiliferous sand into normal crag. At rare intervals very delicate internal casts of univalves, such as turritella, have been exposed by wind erosion showing the pale sand must once have contained fossil shells.

A small excavation was made in the floor of the Creeting pit in order to discover what might be under the Corton Sand. The deposit rests on chalk from which the sand is separated by about twenty inches of stony material resembling the basement bed of the Red Crag which it may well be, since there is undoubted crag at Battisford at about the same level.

H.

E. P.

SPENCER.

THE NEW TELEPHONE EXCHANGE, IPSWICH Map reference 158448 ONE of the all-too-rare opportunities to learn something of geology within the boundaries of Ipswich has been afforded by a large excavation for the basement and foundations of the new telephone exchange building near Barrack Corner.

THE NEW TELEPHONE EXCHANGE, IPSWICH

195 There is a considerable amount of made ground of fairly recent date from about four to over six feet Over much of the area which tends to give a false impression of depth to the excavation.

At one point, where there appears to have been a small pit, a human skeleton was found which seemed to have been roughly thrust into a grave too small for it, this, judging from the condition of the bones, was of recent date.

Under the top soil is a fairly thick mass of unstratified, rather argilaceous gravel, overlying patches of Upper Chalky Boulder Clay. This gravel is contorted and curved streaks of the boulder clay have been caught up in it to a height of about six feet: many of theflintsare frost shattered.

In the main part of the excavation the boulder clay was the lowest deposit which could be examined clearly, but later part of the digging was extended by hand. DĂźring the progress of this work a molar tooth of a mammoth was cut through, part of which was saved and sent to the Ipswich Museum. ' The deposit in which the tooth was found isfluviatilegravel with interbedded sand and silt beneath which is a loamy deposit. The total depth is over twenty feet of which, where the tooth was found, four feet is made soil, 10 to 12 feet of unstratified gravel rests on six inches of undulating dark sand, next comes sharp gravel interbedded with sand to about four feet, below this is one foot of sand becomingfineand silty at the bottom where it rests on sharp gravel similar to the gravel above, and it was here the tooth was discovered.

Similar teeth, as well as those of other prehistoric animals, have been found at various times down in other parts of the town' and particularly in the vicinity of the old Power Station. This is beheved to be thefirstrecorded specimen from the higher ground on the north side of the river.

Recent discoveries from the Stutton Brickearth include a four-foot length of a tusk of Elephas primigenius imbedded on the foreshore, unfortunately, as all too often, it was not well enough preserved for removal; also an incomplete ulna of Cave Lion. These were reported by a local resident whose name I unfortunately neglected to record in writing.

A new addition to the list of mammals from this site is the result of the discovery of an incomplete radius of the extinct fallow deer, Dama clactoniana, formerly Cervus brownei. This is beheved to be thefirstrecord of this deer from this deposit, and perhaps for Suffolk. It is common in the brickearth of similar age at Lion Point (Jaywick), Clacton.

H.E.P.S.