886 PRINCIPLES OF BOTANY, ETC. 
But under what circumstances these probable revo- 
lutions took place, or during how many hundreds 
of years, are questions which are out of the sphere 
of our present researches, and perhaps will never be 
clearly and decidedly answered. : 
S950) 
It is not improbable, that during such great 
changes, soine single productions were entirély lost. 
We have, for instance, in the animal kingdom, 
found several petrefactions, of which the originals 
remain still unknown, and of plants some which, as 
we now well know, are found at a particular spot of 
the globe only. ‘These circumstances seem to prove, 
that some violent catastrophe happened in their pro- 
pagation, by which even perhaps some were lost. 
Thunberg discovered at the Table’ Mountain of the 
Cape of Good Hope, in a single spot only, Disa 
longicornis, and Serapias tabularia, but never after- 
wards any where else. Tournefort found on a 
single rock only of the small island Amorgos in the 
Archipelago, the Origanum Tourneforii. Sibthorp, 
who succeeded him in the same voyage, met with it 
on the same spot, and no where else. 
Countries, now separated by the ocean, were in 
former times most probably joined, at least we may 
suspect this from the different natural productions 
which both have in common. ‘Thus New Holland 
may have been joined to the Cape of Good Hope ; 
and Norfolk island with New Zealand. For in New 
Holland some plants of the Cape of Good Hope 
are found; and New Zealand, which has quite a 
Wells different 
