*S'. H. Warren — Age of Stone Implements. 99 



In this table I have ventured to give ' sequence dates ' to the 

 epochs, after the system that has been used by Professor Flinders 

 Petrie.^ I have not attempted, however, to give a similar value to 

 each unit of the scale, other than that suggested on taking a general 

 view of the stratigraphical successions in various districts. 



In doing practical work one finds at every turn the advantage of 

 these ' sequence dates ' over a system of epochs alone. Where the 

 epoch of implements is but ill-defined, which is very often the case, 

 these ' sequence dates ' are of especial value. Instead of speaking 

 of implements as Acheuleen, which may be far from contemporary 

 with those properly belonging to that epoch, one can assign them as 

 s.d. P. 50-70, or whatever it may be — just so much as can safely be 

 made out. 



I have queried the Ohelleen Epoch, as a matter of doubt. "What 

 one might call the typical river-drift implements were originally 

 called Acheuleen. Subsequently M. de Mortillet- thought that they 

 showed evidence, at Saint-Acheul and elsewhere, of a transition to 

 the Mousterien, and proposed that they should be called Chelleen, 

 the Acheuleen being considered intermediate. Other workers,' as 

 M. G. d'Ault du Mesnil,^ have considered the Chelleen and 

 Acheuleen to be worthy of separation into two distinct periods. 

 M. A. Eutot,* again, looks upon the Chelleen as a phase of transition 

 between the earlier ' Mesvinien ' and the Acheuleen. The point 

 has not been satisfactorily cleared up, but there is evidently a gap 

 between the Earlier PalEeolithic (P. 30-40) and the Acheuleen 

 (P. 60), and, in addition, there seems in some localities to be 

 a series that is of intermediate age. But whether these apparently 

 intermediate forms at P. 40-60 are really to be correlated with 

 the Chelleen of Chelles I am not prepared to say. In using 

 •' sequence dates ' one need not debate the point. Until further 

 exact work has cleared the matter up, it is more prudent to give 

 them a sufficiently wide range to be safe in any event. In the 

 table I have suggested P. 50 for the Chelleen, should that be found 

 to be satisfactory, but for the present it is better to class both these 

 and all other similar series at P. 40-60, and narrow the range 

 down, at one end or the other, as evidence accumulates. 



Local details, wherever these are obtainable, may be written thus : 

 N. 40-60, 1. 30-45, that is to say, there are a series of relics from 

 some locality coming correlatively (but not necessarily contem- 

 poraneously) into the general scale at N. 40-60, of which the 

 particular object or type classed comes into the local scale at 30-45. 

 Or these formulae may be written in the form of fractions or 

 decimals, as may be most convenient for the work in hand. 



There are many more points on which one might say much, but 

 I think that what I have said is sufficient for my present purpose, 

 so I will pass on to consider the question of the value of the mineral 

 condition of stone implements as a test of their relative age. 



1 Journ. Antlirop. Inst., 1899, vol. xxix, pp. 295-301. 



2 "Le Preliist. Antiq.," etc., 1883, p. 133 et seq. 



^ Philippe Salmon: "L'Age de la Pierre," etc., 1889, p. 17. 

 * Bull. Soc. beige Geol. Brux., 1900, vol. xiv, p. 326. 



