70 



near Foxton, which keeps away from the present stream and points 

 up the older valley towards Foulmire, so that the gravel occurring 

 near the latter place would appear to belong to the same series. 



Along the valley of the Bourn Brook there are several 

 patches of gravel at levels intermediate between the Barton 

 ridge and the more recent beds which flank the present brook. 

 The largest of these is at Toft, another occurs near Lords Bridge, 

 and a third lies midway between Spring Hall and Cantalupe 

 Farm; some of the gravel east of the latter place is much about 

 the same level and may be of the same age, with more recent 

 gravel banked up against it. 



The stream in the channel of which these gravels were 

 deposited probably united its waters with those of the Bhee near 

 the junction of the present streams, and the gravel bank 

 extending from Byron's Pool to the vicinity of Trumpington 

 House appears to belong to the same intermediate series. 



The gravel which underlies Croft Town and Newnham is at 

 nearly the same relative level, and it must have been somewhere 

 about this locality that the two rivers, which then flowed north- 

 wards, one on each side of the Trumpington ridge, met to form 

 the Cam or Granta of that period. 



Such appears to have been the aspect of the Cam valley 

 before the time when the river changed its channel for the last 

 time, and took its present course by Little Shelford and 

 Hauxton to join the Rhee near Cantalupe Farm. 



§ c. The gravels which flank the alluvium of the present 

 river hardly merit any particular description, and it will be 

 sufficient to indicate the principal localities where they occur, 

 especially where they have yielded any fossil remains. It may 

 however be worth while pausing to consider how the last 

 change in the channel, introducing the present state of things, 

 was brought about. 



We have seen that the main stream of the Cam, after 

 receiving the Linton brook, continued its northerly course 

 beyond Great Shelford, its western bank being apparently 

 formed by a low ridge of Chalk which stretched across the 

 present site of Little Shelford, and part of which still remains as 

 a narrow strip between the two villages. 



