168 
seen by tbe specimens which I have had cut and polished 
(chosen out of a mass of broken-up stalagmite carried by the 
miners out of Kent's Cavern), that the increase marked by 
annular rings is by no means uniform. And yet uniformity of 
action, and the absence of all change in external surroundings, 
are indispensable to the value of a chronometer. So that we 
can only say of our estimate of years, valeat quantum! Let it 
pass for what it is worth, and no more ! 
When circumstances are favourable, as they must have been 
at some period or periods, in Kent's Cavern, this deposit 
accumulates with great rapidity; thus M. Reclus, in his work 
entitled “ The Earth,"* relates that in the cave of Melidhoni 
the skeletons of three hundred Cretans smoked to death by 
the Turks in 1822, are gradually disappearing under the in- 
crustation of stone, which has enveloped them with its creta- 
ceous layers. 
If we could accumulate a sufficient number of such observa- 
tions, they might, by correcting each other's errors, lead to 
some useful results. But it is obvious that we have not any 
hope of thus bridging over the chasm between a reliable cal- 
culation of 0‘3 inch increment per year, and an utterly unreli- 
able estimate of 0’5 inch in two hundred and fifty years. 
I have accepted Mr. Pengelly's challenge to show on what 
grounds I rest my opinion that his calculations are absolutely 
unreliable. 
In the first place, then, it is to be noted that there is nowhere 
to be found in all the cavern two layers superimposed, twelve 
feet in thickness, of homogeneous and uniform stalagmite. The 
chronometer is absent. 
The first and uppermost stratum met with was a band of 
black mould, over which no stalagmite had formed, the source 
of supply having apparently been exhausted.! The clock had 
stopped for an interval estimated by Mr. Pengelly at 2,000 
years. Beneath this we meet with what is called “ the modern 
stalagmite floor ' ' of very variable thickness, concerning which 
I have this much to say, that if we are to judge by what is 
left, it could not properly be called stalagmite at all. It differs 
wholly in appearance from the true stalagmite, as I noticed in 
one place where the latter had formed upon the surface of the 
* Epoch of l he Mammoth , p. 91. 
t The cave had served as a place of interment, as evidenced by the 
remains of a human skeleton, in the ordinary position of burial ; also by 
cinerary urns (see McEnery, Lit. of Kent's Cavern, p. 34). This early 
explorer found human bones entombed in a pit excavated in the surface of 
the stalagmite (p. 145). 
