1 62 THE ANTIQUITY OF MAN 
thickness, resting on the chalk bluffs overlooking the 
river. To obtain the chalk for the production of cement, 
the overlying gravel deposits have to be cleared away. 
In the process of removal thousands of flint implements 
have been discovered at various levels in the gravel 
deposits. They exhibit a variety of styles in workman- 
ship, many of them bearing evidence of great technical 
skill. In former days the implements were gathered by 
the workmen, and, from them, passed into the posses- 
sion of collectors. Swanscombe became renowned for its 
palaeoliths. 
In the corresponding deposits of the Somme valley, 
Professor Commont,^ by a careful series of investigations 
extending over the opening decade of the present century, 
observed that the implements were always arranged in 
the same sequence or order when the deposits in which 
they occur are rightly dated. It was formerly believed 
that there was no cultural sequence of implements in the 
Thames deposits. Collectors believed that the same 
stratum might yield implements of the most varied types 
of workmanship. To settle the question of sequence, a 
representative of the British Museum, Mr Reginald 
Smith, and one from H.M. Geological Survey, Mr 
Henry Dewey, were delegated, in the summer of 19 12, 
to investigate the implements and deposits of the 100- 
foot terrace at Swanscombe.^ The Associated Portland 
Cement Manufacturers, the owners of the chief pit at 
Swanscombe — at one time known as the Milton Street 
pit, but now as the Barnfield — gave them every facility 
and encouragement in their investigation. In fig. 57, I 
give, in a diagrammatic form, the chief results of their 
inquiry. They found that three series of deposits were 
represented in the 100-foot terrace — each series represent- 
ing formations of a distinct period, each period marked 
by its own form of culture, a distinctive style of flint 
workmanship. The deepest and oldest of the three 
1 See reference, p. 194. 
2 See their report : "Stratification at Swanscombe," Archceologia, 1912, 
vol. Ixiv. p. 1 77. 
