41 



small cutting in stiff grey Boulder Clay, enclosing a lenticular 

 patch of sandy loam, like that on the slope by " The Rivey." A 

 pocket of sandy gravel is also visible, the remnant of a mass 

 which has shrunk to a mere capping on the hill above. 



Westward the clay appears to pass under thick beds of 

 gravel, which cover the country to the north of Clay-pit Planta- 

 tion, and which both northward and westward overlap the 

 Boulder Clay on to the Chalk. There is a small pit in these 

 gravels on the hill summit above the Plantation, exposing 8 feet 

 of compact angular flint gravel stained by iron to a dark brown 

 colour and containing an intercalated band of brown sand ; the 

 materials appear to have been sorted by the action of water, and 

 no large stones were visible at the time of my visit. 



In the road-cutting on the hill-flank midway between this 

 spot and Little Abington Grange, quite a different kind of 

 gravel is exhibited, though it is clearly continuous with the 

 other. A confused mass of chalky gravel and sand with scattered 

 flints and chalk-stones is here seen, looking as if it had resulted 

 from the destruction of Boulder Clay and Chalk in situ; it is 

 probably hereabouts that the Gravel has cut out the Boulder 

 Clay* and impinged on the Chalk, and westward from this point 

 it is always chalky and often intensely so. 



This particular outlier ends at Little Abington Grange, but 

 in the Chalk hollow to the N.W. another mass of Gravel occurs, 

 which hardly makes any feature, but clings apparently to the 

 base of the hill; an excavation in it exposes about 10 feet of 

 coarse gravel, consisting mainly of large flints and chalk pebbles 

 confusedly heaped together without any appearance of bedding ; 

 fragments of quartzite, Septaria from the Jurassic Clays, as well 

 as pieces of Red Chalk and Cambridge Coprolites, are not un- 

 common. The Gravel indeed presents a very similar appearance 

 to that of the Middle Drift in the neighbourhood of Sudbury 

 and Clare, a fades which I take to be a proof of its resulting 

 directly from the destruction of Boulder Clay and Chalk. 



The hill beyond this pit appears to be thinly capped with 

 Boulder Clay, which is seen in the road-cutting by the 50th 

 milestone of the London and Newmarket road, and where the 

 upper two or three feet is rearranged into a reddish loamy soil, 

 containino- stones of various sizes. 



