GEOLOGICAL SECTION. 21 
of savages, who would use the cave as a shelter. That man and 
the hyzena do alternately make use of the same cave was observed 
by Canon Tristram during his travels in Morocco and Syria. Moving 
about in the poor light, the men would drop their implements, which 
would thus become mingled with anything that might be already 
lying on the floor. Finally, the whole was sealed down with Stal- 
agmite. [Stalagmites and Stalactites were shewn, and their origin 
explained—diagram of Stalactite cavern. ] 
Mr. Hichens then proceeded to consider what is suggested as 
to the date of man’s first appearance on the earth by these caves 
and by other lines of evidence. Wherever we look it points to 
great antiquity. First, the Stalagmite. Its nature, consisting of 
thin liminze, shews it to have been formed slowly, and if the perco- 
lation of water through the rock became too rapid, not only would 
there be no formation of Stalagmite, but any which had been already 
formed would tend to be washed away. Again, in the Stalagmite 
of Kent’s cave there are certain inscriptions cut : “ Robert Hedges, 
of Ireland, Feb. 20, 1688,” and “ William Petre, 1571.” If these 
inscriptions are genuine, and if the rate of formation of the Stalag- 
mite has been uniform from the first, it is clear that it is exceedingly 
slow. It wasshown that the rate of formation had probably been 
uniform : where there is copious drip now, there is the Stalagmite 
thick: where there is little drip, there is next to no Stalagmite: 
and the reasons for believing the inscriptions to be genuine were 
given. Macenery’s account of the ‘‘ Robert Hedge’s” one almost 
accurately describes it as it stands now, and yet it was written more 
than fifty years ago; and with regard to the older of the two, the 
three questions, “ Was Kent’s cave known in 1571?” “ Did William 
Petre exist ?” “‘ Was William Petre, if he existed, likely to have cut 
the inscriptions ?” were all answered on the affirmative, so that the 
inscription is probably genuine. Mr. Pengelly considers that here 
the Stalagmite is formed at the rate of 1-20th of an inch in 250 years ; 
and yet in Kent’s Cave in one place it reaches a thickness of twelve 
feet ! 
Next, the consideration of the animals which were contemporary 
with man leads to the same conclusion. They belong to three 
different groups—those, eg., horse, still living in England, those, 
e.g. the brown bear and reindeer, living in other parts of the world, 
but no longer in England, and those, ¢.g., the mammoth and cave lion, 
quite extinct. Now, every known fact suggests that the causes 
which lead to the extinction of groups of animals act very slowly, 
