2 2 S MR. W. G. CLARKE ON NORFOLK FLINT IMPLEMENTS. 
is so fine as to be indistinguishable from that by the sandy 
site people, and it is not improbable that these implements 
were made later in the Neolithic period than those of other 
boulder clay sites. 
Thinking that in the different groups there would probably 
be varying proportions of implements with portions of the 
original crust remaining, and also with the top of the bulb 
of percussion removed by a single chip, I examined 316 of 
the Cissbury type, 1355 of the boulder clay type, and adopted 
the figures given in last year’s ‘ Transactions ’ with regard 
to 593 implements from Thetford district, chiefly from sandy 
sites, with a few boulder clay and polished. In the first and 
third groups the majority of the implements are probably 
made of flint excavated from the chalk and the proportions ' 
with chipped bulbs of percussion are 38.9 and 47 per cent, 
respectively ; in the second group where the implements are 
chiefly made from nodules, not flakes, the proportion is 20.5 per 
cent. As might be expected, the proportion of implements 
with pieces of the outer crust still remaining on them, is much 
greater in the boulder clay than in the other groups, being 
46.8 per cent, in the Cissbury type, 47 per cent, in the sandy 
site type, and 71 in the boulder clay type. That the 
percentage of crust in implements of the boulder clay type 
is fairly constant is proved by three instances. On a typical 
boulder clay area, that on the table-land west of Norwich 
and between the rivers Yare and Wensum, the proportion 
of implements (581 in number) with chipped bulbs is 18.9 per 
cent, and those with crust 73.1 per cent. ; in 333 implements 
from Ringland, the proportions are 26.7 and 70.2 ; and in 
150 implements collected by Mr. W. A. Dutt in north-east 
Suffolk and along the banks of the Waveney, the proportions 
are 9.3 and 69.3. 
(3) Late Neolithic, or Sandy Site type. The implements 
found on typical sandy sites, chiefly in the south-west of the 
county, are as a rule chipped, occasionally chipped and 
rubbed, and splendidly finished. They mark the height of 
perfection which the art of flint-working attained in Neolithic 
times. Not only is the workmanship of the implements from 
