part 3] PLEISTOCENE DEPOSITS ABOUND CAMBRIDGE. 221 



to the Observatory Gravels. Mr. H. V. Sheringham, who superin- 

 tended the making of the drain, believed that the loam -was banked 

 against the gravel. It must, however, be remembered that a clay 

 with ; race' and rootlets occurred below the Observatory Gravels in 

 one place at the North Pit, Traveller's Rest. 



It is doubtful whether any fossils have been obtained from the 

 clay. One land-shell seen may have been introduced from the 

 surface. On the heap of clay thrown up from a drain in Christ's 

 cricket-ground, I picked up a dove-grey nueleiform implement, 

 which, however, may also have been forced in from the surface. 



The origin of the clay is a matter of considerable importance 

 when we try to establish the sequence of events in this area, and 

 it is to be hoped that further light will be thrown upon these 

 accumulations, which have not hitherto been recognized in the 

 vicinity of Cambridge. 



(d) The Upper Barnwell-Village Beds. 



These, like the Lower Barnwell-Village Beds, are largely found 

 in the deposits constituting 'the Highest Terrace of the present 

 river-system ' of the Geological Surveyors, the upper part of which 

 is usually not much above or below the 50-foot contour-line. On 

 the Histon Road, and also at the Mill-Road Cemetery, the gravels 

 rise to a height of 54 feet, which is approximately that of the 

 lowest level at which the Observatory Gravels are mapped near 

 the Madingley Road ; but there is a great spread of gravel north 

 of Cambridge on the west side of the Cam, and it may contain 

 deposits of various ages, some formed during aggradation, others 

 during general valley-deepening. The full history of these deposits 

 awaits elucidation. The sections of which Ave have much informa- 

 tion lie a little below the 50-foot contour-line in Barnwell Village 

 (where there are now no exposures), at Elfleda House, on the 

 Newmarket Road, a quarter of a mile east of the second mile- 

 stone, and near the junction of the Chesterton and Milton Roads. 

 Chesterton. The gravels of Elfieda House are mapped as belong- 

 ing to the Ancient River- System, but the}' grade with the upper 

 gravels of Barnwell Village, and the fossil evidence is in favour 

 of these belonging to that series. If that be so, the difficulty 

 pointed out by the Geological Surveyors, due to the greater height 

 of the ' ancient " gravels on the Observatory ridge, vanishes. 



1 need not describe the sections in the various pits — this has often 

 been done. It will be remembered that in some places at Barnwell 

 and Chesterton, though by no means generally, Corbicula loams 

 occur at the base of the deposits. At Elfleda House they appear 

 to be absent. 



The points to which I wish to draw attention are concerned 

 with the palseontological evidence, which is distinctly in favour of 

 the set of deposits under consideration being referred to the Upper 

 Palaeolithic period. 



I am not aware that any shells have hitherto been obtained in 



