536 Dr. Marr — Palceolithie Implement, Cambridgeshire Gravels. 



The face of the pit was extremely steep, and the irapleraent could 

 not have fallen from above and rested where it laj', namely, on 

 a sloping ledge about 4 inches wide, with the face of the gravel 

 above and below nearly vertical. The greater part of one face of the 

 implement was exposed on the ledge, and on removing the flint its 

 ' mould ' remained in semi-coherent sand. Some of this sand still 

 remains firmly cemented in one or two little depressions of the 

 implement. There is no doubt, therefore, as to its occurrence in situ. 



The implement itself is well fashioned, of ovoid shape, formed of 

 brown flint, and but little worn. The point has apparently been 

 broken off during manufacture or when in use, for the patina on 

 the fracture is similar to that over the dressed surface. It measures 

 3-iV inches in length by 2f in breadth at the widest part. I have 

 deposited it in the Sedgwick Museum. 



Its occurrence about 100 feet above the present river level at 

 Hildersham is of interest, but is not contrary to what might 

 reasonably be expected. Some 5 miles in a northerly direction lie 

 the elephant-bearing gravels near Lark's Hall, at a height about that 

 of the gravels we are considering. They there occur in a valley, and 

 are traceable from thence almost continuously (save where cut through 

 by the modern Cam near Cambridge), along the ridge of Wilbraham 

 and Quy Church past the Observatory and away northward into the 

 Fenland. Were it not for subsequent denudation by the Granta, the 

 Hildersham gravels might be traceable in the same way past Babraham 

 and Shelford, and so northward to join the gravels mentioned above, 

 near Cambridge. 



Although the implement found by Mrs. Hughes near Upper Hare 

 Park was associated with gravels which are not inserted on the 

 Geological Survey Map, and the views of the surveyors as to their age 

 are therefore unrecorded, their position would suggest that they might 

 belong to the period of formation of the Q,uy Church and Wilbraham 

 gravel. It is desirable that further search should be made in these 

 high-level gravels in various parts of the county, as was indeed long 

 ago suggested by the late Sir John Evans (see Dr. Bonney's Cambridge- 

 shire Geology, p. 56). 



The Cam has eroded its valley at Cambridge to a depth of nearly 

 50 feet below the level of the Observatory gravels : there is, therefore, 

 little cause for surprise if erosion has taken place to about double that 

 amount at Hildersham. In fact (even allowing for a larger volume of 

 water), a grade steeper than that of the present Cam, which falls about 

 80 feet between Little Abington and Cambridge, is probably necessary 

 to account for the transport of the coarse flint pebbles which largely 

 compose many beds of the Observatory gravel. The fall from 200 feet 

 to 60 feet (which is the difference in height between the Palaeolithic 

 gravels of Hildersham and the Observatory gravels) in a distance of 

 about 12 miles measured in a straight line, or, allowing for sinuosities, 

 say a fall of 10 feet per mile, does not appear too much to allow for 

 the transport of these flints. 



The mere existence of an implement of the type found in the 

 Hildersham gravel renders it unlikely that the gravel belongs to the 

 ' plateau series ', and points to its assignment to one of the older river 



