10 
found in the gravels and silts of existing rivers, when they ran at 
100 or 150 feet above the present and historical levels, and were 
just beginning to excavate their present valleys. Nor to the 
deposit of similar remains, often securely sealed under thick sheets 
of undisturbed stalagmite, in caves, which are the courses of 
underground rivers in limestone districts, which must have ran 
when the drainage and valley systems of the district were totally 
different from those at present existing. These are two well 
known to all who have the slightest acquaintance with geology to 
require any repetition, and I will confine myself to a few of the 
most striking and recent instances which carry to any unpre- 
judiced mind the conviction of the immense duration of the 
quaternary period, and of man who is one of its most 
characteristic fauna. 
Tue Lesson oF THE CHALK CLIFF. 
Dr. Evans gives a striking picture of what the palzolithic savages, 
whose implenients are found in the gravels of the old Solent river 
now 100 feet above the present sea level at Bournemouth,must have 
seen looking southwards over what are now Poole and Christ- 
church bays. This old river has been traced by its gravels, 
sloping to the east, from the Dorsetshire Wolds, intercepting the 
small rivers, such as the Avon, Test, and Kennet, which ran into 
it from the north, and finally falling into the sea beyond 
Portsmouth. Stich a river could only have run when the land 
extended beyond it to the south, and the sea was barred out by a 
continuance of the chalk downs between the Isle of Wight and 
Dorsetshire. The two extremities of this range at the Needles 
and at Ballard cliff, though now twenty miles apart, correspond 
like the two parts of an indenture, and show, by their outlying 
pinnacles or needles, the exact process by which the sea is 
gradually eating away a solid chalk cliff which has been upheaved 
so that the strata are nearly vertical. 
Very Earty IMPLEMENTS. 
But a still more striking instance of extensive denudation has 
been just discovered,to which I refer with the more pleasure as it 
shows what good to science may be accomplished by societies like 
this,or even by single individuals who take an intelligent interest 
in this question. Mr. Harrison, a shopkeeper in the village of 
Ightham, in Kent, is also a field geologist, and spends a good deal 
of his leisure time in exploring the gravels of the chalk North 
Downs, and of the ridges of the Wealden, which bound the 
valley in which he lives. At various points in these grounds, at 
high levels far above those of the existing streams, he found a 
number of paleolithic implements, of arude type but unmistak- 
ably of human origin. Having communicated this interesting 
discovery to Professor Prestwich, the Professor went down to the 
