5r 



S.W., and showed a hollow filled with gravel, shelving up to the 

 North but gradually deepening towards the Observatory grounds, 

 and about 8 ft. deep at S.W. end. 



I think it may have been hereabouts that the series of 

 deposits first described in the higher parts of the Cam Valley 

 was united to that coming from the east ; the former must have 

 descended the valley, and since the gravel-covered ridge now 

 makes a sharp turn to the N.W., this may have been consequent 

 upon the junction above suggested. 



Several old gravel pits occur along the high ground between 

 the Observatory and Girton College ; at the latter place a well 

 was sunk 10 feet into gravel without touching the gault below. 



Most of Girton stands on gravel or sand, and where exposed 

 the pebbles are seen to be -mall and much rolled. From Girton 

 the ridge bends slightly to the north-east, and then turns again 

 to the north-west ; below Histon Church however it is cut 

 through by a little brook which flows off the lower gravel plain 

 to the eastward, and has made a valley for itself through this 

 still older series of deposits. Another breach is made by two 

 small streams coming in from the south-west near Oakington, 

 and re-deposited gravel occurs in both valleys, so that there is 

 much confusion in the gravels here. 



Above Oakington however the high ridge commences again, 

 and continues steadily towards the north-west between Long 

 Stanton and the Huntingdon railway ; in the cutting on this 

 line, about midway between the Long Stanton and Swavesey 

 Stations, gravel is seen overlying Oxford Clay, and thence a 

 gravelly soil extends on the north side of the line as far as Over, 

 where gravel has been obtained from pits along the slope facing 

 the river Ouse. This river, like the Cam, has cut directly through 

 the ancient line of drainage, which appears to have taken a bend 

 to the north hereabouts, washing past the clay slopes which jut 

 out above Bluntisham and Colne. Gravel occurs at and west of 

 these places, but its precise relations are rather diflficult to 

 ascertain; it is furrowed by transverse valleys and appears to be 

 flanked by more recent Fen-gravels. 



At Somersham its disposition is more readily comprehended : 

 it underlies the whole of the town, and caps the high ground to 

 the north and north-west. A good section of it was visible 



