146 
PrwuBval Man in the Valley of the Lea. 
see it. The alluvium of the Lea Valley has not been 
seriously disturbed since Neolithic times, neither have the 
levels been materially altered. The climatal conditions have 
of course been quite different from what they were in 
Palaeolithic times; the river has not run in historic times as 
a rapid shallow torrent laden with blocks of ice and large 
stones as it did in Palaeolithic times. It is now a quiet 
stream, with no power to bring down huge stones and 
uncountable tons of gravel; neither has it the power now 
Fig. 24.— Three Neolithic Celts, found near Temple Mills, Essex. 
to excavate the valley as before. The Thames itself has not 
excavated its valley near London since the Neolithic period, 
say for 2000 years. If the changes from Palaeolithic times to 
now have been gradual, as all the evidence seems to show, 
and if in 2000 years, or from 2000 to 10,000, no great 
change has taken place in the levels, how immensely far off 
the time seems to be when the level of the Thames was at 
least 160 or 170 feet higher than at present. How enormous 
