594 
A small stream runs past the town of 
Ightham where it joins the Medway. This 
stream has the usual terraces in its valley 
which, like other terraces, are formed of river 
drift. These valleys contained paleolithic 
implements of the usual kind similar to those 
heretofore described. The theory was, that 
the river-valley had been eroded, the sand 
and gravel cut or washed away, then carried 
down the stream and deposited where the 
current became weaker; thus would be in- 
volved all the paleolithic implements within 
the scope of the valley or ravines that fell 
into it. The information furnished by Mr. 
Harrison’s discovery was that, on the high 
plateau levels not involved in the valleys or 
the ravines leading to it, the same kind of 
paleolithic implements were found practi- 
cally on the surface. The theory of Pro- 
fessor Prestwich founded on Harrison’s dis- 
covery carries us back one step further in 
the chronology of paleolithic man. He be- 
lieved that the implements were made and 
used by man on these high plateaux before 
the commencement of the formation of the 
river-valley ; that, being scattered over the 
surface where they had been left by their 
owners, they have remained until now 
found undisturbed, uninfluenced by the 
erosion, the which as it proceeded, cut 
away the sand and gravel and drew the 
the other implements into the valley or 
into the general current which carried 
the sand and gravel down, and deposited 
them with the débris in the form of a 
terrace. These Harrison implements not 
being within the reach of this erosion, re- 
mained in situ and are now being found on 
the surface of the plateau above. Imple- 
ments, and even workshops indicated by 
the presence of certain tools and style of 
implements, remained on the high plateaux 
and are there found to-day. If they had 
been within the influence of the stream and 
had been carried down by its waters, they 
would have been found in the drift of the 
SCIENCE. 
[N. 8. Von. X. No. 252. 
terrace below ; but not having been thus in- 
volved, they were not affected and so re- 
mained in their original places until now 
found. This conclusion, if correct, pushes 
the paleolithic one epoch farther into the 
past ; instead of the implements being found 
in the bottom of the river terrace at the 
completion of their journey, they are found 
on the high plateau which was originally, 
and for the others, the beginning of the 
journey. 
Tertiary Man. 
Another step in the science of prehistoric 
anthropology (whether forward or back- 
ward is yet to be determined) was the 
discovery of implements and objects of 
supposed human origin, or which bore a 
supposed artificial character, alleged to 
be evidence of man’s existence in the ter- 
tiary period. The first report in this di- 
rection was by Mons. J. Desnoyers who, 
on June 8, 1863, presented before the 
Academy of Sciences at Paris, certain fossil 
animal bones and pieces of wood, from the 
quarries of sand and gravel at Saint Prest, 
near Chartres, France, which were believed 
to belong to the pliocene formation, whose 
marks, imprints and striz were such as 
could have been made by man and were, 
therefore, said to be evidence pointing 
towards his existence in that period. In 
1867 the Second Congress of Archeology 
and Prehistoric Anthropology met at Paris 
and was largely occupied over ‘a presenta- 
tion of, and discussion upon the evidences 
of tertiary man. Mons. L’Abbé Bourgeois 
presented a series of flint objects which 
were so chipped or broken as to appear to 
have been done by man. Other objects 
were presented by various persons, all al- 
leged to have a bearing upon the main 
question and tending to establish the exist- 
ence of man in the tertiary period. These 
were of different materials: bones cut or 
marked, teeth or bones drilled, wood and 
bone carved or gnawed, ete., until a rather 
