224 MR - w - G - CLARKE ON NORFOLK FLINT IMPLEMENTS. 
dark grey and of two as light grey, one of the latter being 
the only piece of flint which had lost its crystalline appearance. 
In a few cases the surface was partly decomposed. The 
interior of these implements varies from black to blue and grey, 
and it may possibly be that the two latter are changes in the 
process from black to white, with a concurrent change in the 
texture of the flint from crystalline to opaque. It is certain 
that the first external weathering on the sandy site Neoliths is 
a bluish colouration, all shades and stages of which occur. 
In some the colouring is as delicate as the bloom of a peach ; 
in others it is a decided patina of measurable thickness. On 
a small pointed scraper, a sandy site type, I found on Rushford 
Heath, the base of the implement appears to have been 
protected in some way, and has retained its original colour, 
but the pointed end shows various stages of weathering from 
blue to white. The investigations of Mr. B. C. Polkinghorne,* 
seem to prove that the alteration of colour in Cissbury type 
implements is due to the “ dissolving out of the more soluble 
colloidal silica by rain-water charged with carbonic acid.” 
This white weathering seems to be one proof of the antiquity 
of these implements compared with others of the Neolithic 
age. Another is furnished by the absence of rubbed imple- 
ments at the flint-workings. At Cissbury a single fragment 
of a polished axe was found one foot from the surface in a pit ; 
they are equally rare at Spiennes, where the flint pits are on 
a larger scale than either at Grimes Graves or Cissbury. In 
Grimes Graves a polished basalt axe was found, but neither 
at Massingham nor Ringland have rubbed implements been 
known to occur. Further proof of the antiquity of these 
implements is provided by their partial rechipping in later 
Neolithic times, for the exposed dark inner flint is unaffected 
by the changes of several thousand years. Forty per cent, 
of the Ringland implements appear to have been rechipped, 
generally for use as knives or hollow scrapers. 
The varieties of implements of the Cissbury type are few ; 
most have but little secondary chipping and that chiefly on the 
edges ; the flaking is bold and the implements bulky. This 
* 1 Neolithic Man in North-east Surrey,’ p. 1 S 2 . 
