3 
* 
presumptions of a secondary kind. First, certain flints from 
Brixham Cave, the valley of tlie Somme, and caverns in Bel- 
gium, are affirmed to have been plainly fashioned into tools, 
spears, or hatchets, by the hands of savage men. And next, 
the beds of gravel or stalagmite, where they were found, are 
said to have been deposited many myriads of years ago. 
Human deposits are thought to occur in quaternary strata or 
drift, directly after the close of a great ice period. This 
period, again, has three different estimates of its remoteness 
by different geological speculators. One of them assigns two 
glacial periods to the dates 13,000 and 44,000 years before 
Christ. Another offers the dates 210,000 and 850,000 years 
B.C. for a Post-Pliocene and a Miocene glacial period, while 
others have suggested a date still more remote for man’s first 
appearance on the earth. 
3. Mr. Whitley, in two able papers read before this Society, 
denies even the first premise. The so-called flint implements 
were formed, he thinks, by the natural change of flint nodules 
broken under strong pressure. He offers many reasons — 
from their position, their great number, their relation to the 
neighbouring beds, and the effects of artificial fracture, to 
support this view. Mr. Patti son agrees with Mr. Whitley as 
to a large proportion of the alleged implements, but admits 
that some are apparently of human origin. He maintains, 
however, on a full review of all the features both of Brixham 
Cave and the valley of the Somme, that six or seven thousand 
years are time enough to account for all the later changes. 
Mr. Callard, in his short and able essay on the Geological 
Evidences of Man’s Antiquity, argues forcibly for the same 
view. Whethef or not Mr. Whitley is right in his denial of 
an artificial origin to each and all the so-called implements of 
the Drift, I think that Mr. Pattison and Mr. Callard are fully 
justified in their dissent from the other main premise of the 
theory. It may be shown that there is no scientific proof of 
these immense ages since the close of a real or imaginary 
glacial epoch, but only a series of mere conjectures, based on 
wholly inadequate data ; and a more probable theory than any 
of those hitherto offered would reduce the distance of man’s 
first appearance within a limit in complete harmony with the 
Scripture statement. Man has, doubtless, been contemporary 
with many animals now extinct ; but this can never prove his 
entrance on our planet to have been 200,000 or even 20,000 
years ago. 
The theories I shall examine in succession are these : — First, 
Sir C. Lyell’s doctrine of uniformity; secondly, the thermo- 
dynamic theory of Sir W. Thomson ; thirdly, the excentric-pre- 
b 2 
