35 . 



cut back its edge into a deeply indented line, and the whole of 

 the valley from Little Gransden by Abbotsley to St Neots 

 having evidently been excavated through the Drift by similar 

 fluviatile action. 



The Boulder Clay continues to cap the hills bounding the 

 north side of this valley until this opens out into the main 

 valley by St Neots. 



These drift-covered hills stretch northward into Huntingdon- 

 shire, but on the eastward slopes the action of rain and streams 

 has cut back the Boulder Clay, causing its boundary to re-enter 

 Cambridgeshire by Graveley, Yelling and Papworth St Everard. 

 The most noticeable feature to be observed along the northern 

 edge of this great spread of clay is the way in which it runs out 

 along the projecting spurs and hills separating the valleys by 

 which it is here indented ; the bounding line may thus be traced 

 eastward from Elsworth, retreating up the hollows and curving 

 round the hills by Knapwell, Boxworth, Lolworth, Drayton and 

 Madingley to the high ground above Coton, the summit of which 

 is registered at 175 feet above the sea. 



South of this it is cut back by the valley of the little brook 

 which rises near Hardwick, but running out again on the other 

 side along the broad spur of Barton Field, it returns finally 

 along the southern slope of these hills and bends south-west- 

 ward to Toft and Caldecote ; thence it descends into the valley 

 of the Bourn, and crossing over by Kingston runs nearly up to 

 Eversden Wood and into the long spur which was first described. 



Mr H. H. Howell, who has surveyed a great part of the area 

 (of which the circumscribing limits have been traced in the pre- 

 ceding paragraphs), informs me that it is covered almost 

 entirely by grey or greyish-brown imstratified clay, its colour 

 and contents varying somewhat according to the locality and 

 the particular formation which happens to underlie it, but 

 fragments of chalk and chalk flints are found everywhere in 

 more or less abundance ; Oolitic rocks of the immediate neigh- 

 bourhood are likewise present in great quantity ; ice-scratched 

 fragments of the older formations, chiefly from the New Red 

 Sandstone, Coal-measures and Carboniferous limestone, are 

 found, but much less frequently ; pebbles and blocks of Basalt 

 and other igneous rocks also occur occasionally. 



8—2 



