78 Mr Baird on, the Geology of the 
together, the interstices only between them being filled with the 
tufaceous basis. 
That this conglomerate limestone is a much later formation 
than the interior mass, appears from the well-known and inter- 
esting fact of bones and teeth of large quadrupeds having been 
discovered imbedded in it. 
The solid limestone, from the occurrence of beds of flinty 
slate in it, would appear to be a transition, or a very old secon- 
dary limestone, and it is extremely improbable, that organic re- 
mains of animals, so high in the scale of being, should be found 
in it, or in any rock contemporaneous with it. I have seen 
some of these petrified bones of large animals, and they were 
always imbedded in the conglomerate rock. Shells also occur 
in it, but always land-shells, aild similar to the common species 
on the hill. These shells often are not at all altered. Some 
parts of this conglomerate are certainly of later formation than 
other parts, and I have no doubt that though slowly, its forma- 
tion is daily going on. 
There is a considerable depth of soil on some parts of the 
hill, in particular near its foot. It is a red, calcareous kind of 
soil, formed in a great measure from the mouldering of the 
calc-tuff; and appears to be very productive. 
It is highly improbable, I think, that this calc-tufT basis has 
been deposited over the debris of the solid rock, from water 
which at any former period stood over the hill. Though I 
do not recollect that springs are very numerous on the hill, 
yet I think that it is far more probable that this calc-tuft* 
has been deposited from such springs, as is usual with this 
substance in other situations, or from water percolating through 
the sides of the hill, and supplied, if necessary, from some great 
central reservoir, which I believe is not at all an uncommon cir- 
cumstance in limestone rocks. The calc-tuff thus formed, and 
enclosing the debris of the solid limestone with animail remains 
of various kinds, explain the structure and nature of this rock 
and its petrifactions. It is probable, therefore, that petrifactions 
of animals of the latest formation, or even of man himself, may 
be discovered in this and similar rocks. 
Numerous caves occur in the limestone, the sides, roofs, 
and floors of which are lined with a thick coating of calc- 
