51 



drainage, tbey have been exposed to greater denudation and 

 fewer portions have escaped destruction ; in the other case the 

 stream has been diverted into another channel, and the older 

 beds have been left in a much less patchy and discontinuous 

 state. 



In the Linton valley, S.W. of Bartlow, there is a patch of 

 gravel which has also been referred to the Middle Drift, but 

 which may not improbably belong to a branch of the present 

 series. It is well seen in a large pit near the station, which 

 exposes some forty feet of fine chalky gravel, iron-stained, and 

 piped at the top, with many thin bands of sand and loam in the 

 central part, and very chalky gravels below, all the beds 

 dipping S.S.W. at an angle of 15". 



Two smaller neighbouring pits present the same features, 

 and the whole mass appears to be banked up against the chalk 

 slope ; Boulder Clay caps the hill above and comes very near 

 to the edge of the gravel, but does not appear to overlap it. 

 Patches of gravel occur at about the same level further down 

 the stream on either side of Linton ; that which is seen about 

 Pampisford Station and Abington Park may be of the same 

 age, though it is difficult to separate it from lower and more 

 recent gravels. But in the cutting half a mile N.W. of the 

 Station gravel is again seen lying in a hollow of the chalk, and 

 thus appears to be continued into an elongated patch capping 

 the high ground by Pampisford Hall. The end of this outlier 

 points directly for the \yhittlesford mass, and may once have 

 been continuous with it before the excavation of the present 

 valley ; it seems probable therefore that somewhere in this 

 neighbourhood the three streams whose gravels Ave have traced 

 down their several valleys were united into one river. 



But what course did the confluent waters subsequently 

 take ? This is a question by no means easy to answer ; there 

 are beds of gravel at various altitudes lower down the valley, 

 but even the highest of these appear to belong to a series which 

 is the production of later times. Moreover the probable con- 

 nection of the Whittlesford and Pampisford patches seems to 

 indicate that the old river flowed either in an easterly or a 

 westerly direction. Now it is to be noticed that the Whittles- 

 ford ridge is prolonged for some distance to the N.W., and 



4—2 



