13 
3. Spring floods of great power, such as now occur in Arctic’ 
regions. 
4. Sea action. 
5. A slow movement of elevation. 
Mr. Boyd Dawkins, in his ample and able researches into the 
subject, embodied in his most interesting book, referring to 
the Victoria Cave at Settle, estimates that the two feet of debris 
accumulated at its mouth since the ancient British period, 
supplies a chronometer, and indicates the lapse of 1,200 years. 
He applies this to the six feet between this and the floor of the 
men of the polished stone period (neolithic) , and thus makes the 
latter 3,600 years ago ; and then to the still earlier (mammoth) 
age, which brings the occupation of the cave by man to about 
5,000 years ago. But he admits that in ancient times the frosts 
may have been more intense than they are now, and therefore 
that the rate of weathering may have been faster.* Thus the 
calculation is invalidated, and one-half the number of vears has 
equal claims on our belief, — or superior, if favoured with other 
considerations. 
There are a sufficient number of good instances of the occur- 
rence of bones with palaeolithic implements only, to warrant 
the conclusion that the early cave period is synchronous with 
that of the gravels. The cave was the resort of the first 
hunters. 
The most remarkable and complete of the Belgian caves are 
those on the Meuse and its tributaries, described in the able 
work of M. Dupont, Director of the Natural History Museum 
at Brussels. f No less than forty-three caverns which open in 
the limestone cliffs of the Meuse or its tributaries have been 
carefully explored ; of these, twenty-five have furnished remains 
of man’s work associated with extinct mammals. The caves 
open at heights varying in different parts of the valley from 
12 to 60 yards from its level. They all have a floor of ancient 
mud, the result of periodical inundations of the river. Some 
of the bones were thus washed in, but the greater part were 
accumulated during occupation by living men and animals. 
We select one of the twenty-five caves, — that of Macjrite, near 
Pont-a-Lesse. Dry, large, open, light, it has been often chosen 
as a convenient abode. Its floor is covered with rolled pebbles 
and 2^ yards of river mud, including four distinct successive 
surfaces, and each layer containing bones. These remains vary 
* Prestwich, p. 115. 
t L’ Homme pendant les Ages de Pierre dans les Environs dc Dinant-sur- 
Meuse et Bruxelles. 1872. 
