30 MR. W. G. CLARKE ON REMAINS OF THE NEOLITHIC AGE. 
partially polished, are possessed by a Nottingham collector. 
Mr. F. Rix (Thetford) has a large polished knife from Snarehill ; 
Mr. F. Russell (Thetford) an ashleaf arrowhead from the 
Abbey Heath, of which the more obtrusive angles have been 
rubbed off ; and Mr. W. A. Dutt (Lowestoft) has the cutting 
half of a white axe, partly polished, from Weeting ; a blue 
flint knife with one side of the cutting edge ground and 
the other chipped, from Santon Downham ; and a fragment 
of a circular knife with both sides of the edge ground from 
the same place. Mr. P. R. Clarke (Norwich) has a rubbed 
knife, a rubbed axe of white flint from Snarehill, and an awl 
from Santon which had been rubbed on three surfaces, 
including both sides of the projecting point which forms 
the awl proper. In addition, the edge of this point has been 
most minutely chipped. In every case — except the Barnham 
axes — these rubbed implements are of flint, but in Grimes’ 
Graves a ground axe-head of diorite was discovered, of a 
type usually found in Yorkshire. Specimens in my own 
collection are a white flint discoidal implement from Santon, 
rubbed on one edge — perhaps the beginning of a knife ; a 
polished axe from Navarino, Thetford ; a rubbed fabricator 
from Barnham Common ; a triangular graver from Thetford 
Warren (fig. 5) ; a delicately chipped single-edged knife on 
which the rubbing extends from the central ridge to the 
side ; and a piece of polished ivory (fig. 6) found near 
Thetford Waterworks, and considered by Mr. C. H. Read of 
the British Museum to have probably been used with a thong 
as a weapon of offence. 
In practically all cases the bulk of the chipping on an 
implement is on the side opposite to the bulb of percussion. 
On a certain proportion the top of the bulb has been removed 
by a slight chip. This has been done on 174 specimens out 
°f 593 - With present day flint-knappers the fractured bulb 
is the exception, but a practised knapper can fracture the 
bulb intentionally nine times out of ten by the peculiar 
method of striking off the flake. The sole benefit of this 
operation would seem to be in affording a better grip than 
the rounded bulb would render possible. 
