10 
On tJie Caves Perforating Marble 
In conchiding this sketchy article on the caves, a few 
remarks on the beds they perforate may be interesting. It 
has been shown with reference to the Limestone Creek 
marble beds that the surface outcrops, and also those within 
the caves, are intersected with thin yellow seams parallel 
to the bedding planes, and it is conjectured tliat these seams 
can hardly be due to the percolation of surface waters 
holding colouring matter in solution, because of their regu- 
larity and pai’allelism. Whether the intense subterranean 
heat, which it is probable caused the metarnorphism of the 
calcareous sediments into crystalline marbles, lurs obliterated 
all traces of bedding at a depth, and so produced a homo- 
geneous mass of saccharoidal marble, I am unable to suggest; 
but in regard to the origin of the marbles the evidences are, 
I think, in tixvour of their having assumed their crystalline 
form during shrinkages in the earth’s crust at the close of 
the Silurian or at the beginning of the Devonian periods, 
when the whole series of sedimentary rocks were inclined at 
high angles — i.e., folded and bedded together by the dynamic 
and metamorphic agencies of nature — and, after long-con- 
tinued periods of subaeiial or subaqueous denudation, were 
again submitted to the influence of plutonic forces, during 
Avhich the fragmental porphyries which at present rest on 
the ixpturned edges of the sediments were deposited. That 
the latter are the results of either subaeiial ash, or sub- 
aqueous tuff, grouped round such probable volcanic centres 
as Wombargo and Cobboras mountains,* is, I think, evident 
enough from their lithological character and their strati- 
graphical position. It is hardly piobable that the deposition 
of the porphyries over the palmozoic sediments would cause 
such extensive metarnorphism of the calcareous beds; in 
fact, the proof that such is improbable is seen at Stony 
Creek, for here the unaltered fossiliferous beds are in direct 
contact with the overlying porphyries, while the crystallisa- 
tion of the rock masses appears to increase with the depth 
below the surface. 
In my examinations of the Stony Creek marble beds I was 
fortunate in finding some fossils, which Professor M'Coy has 
been good enough to examine, and has identified one shell, 
spirigina reticularis, which he states is one of the few 
* Vide A. W. Howitt in Progress Report, Geological Survey of Victoria, 
1876, p. 200. 
