32 
THE GEOLOGIST. 
dually increasino; in thickness until a cliff is exposed some 50 to 80 feet 
high, formed of the first-mentioned beds above, and the latter lying in con- 
formable stratification at the base. 
These latter beds are some\Ahat remarkable near this place (Pic-nic 
Point) for being filled with a vast number of tubular-shaped bodies, covered 
on the outside with warty excrescences. These tubes vary in size from 
the thickness of a straw to that of a man's wrist. Witliin them there is 
generally found a core, easily removable by a little gentle pressure. The 
outside of the tubes in question being harder than the other portions of 
the strata, they, of course, resist the action of the waves more successfullvi 
and stand out from the containing matrix in singularly bold relief ; often, 
when half imbedded, reminding one of some huge chiton clinging, for bare^ 
life, to his stony habitat, upon which he has been left high and dry by the 
receding tide. Although bearing a very strong resemblance to fossils, the 
appearances witnessed are generally regarded by local geologists as due 
to the decomposition of hematite, with which the same kind of rock is 
known to abound. 
The upper beds in this particular spot, represented by a soft arenaceous 
stone, do not appear to be fossiliferous,butalso contain certain tubular bodies 
— very different, however, from those last mentioned — generally traceable 
for many inches at a time, and of a chalky appearance, Having for- 
warded a small hand-specimen to the Eev. J. E. AYoods, of Penola, that 
gentleman suggested they might be a species of fulgurite due to the ac- 
tion of lightning, — a theory which seemed to be especially favoured by 
the tubes being invariably found in the higher portions of the strata, and 
nowhere traceable at a few feet from tiie surface. Subsequent observation 
has, however, would seem to show that these appearances must be referred 
to a far less romantic origin than " the fire of Jove ; " in fact, on exami- 
ning them more closely, many appeared to be filled with a black and 
crumbling substance resembling decayed vegetable matter, and on search- 
ing still further, I discovered one in which a piece of wood, evidently the 
root of a shrub or tree, was still contained. Since then I have met with 
similar specimens in Melbourne among some Tertiary rocks near tlie gaol, 
and also at Xorthcote, where a thin capping of newer Pliocene deposits 
rests on the Silurian strata. In this latter instance I observed many re- 
cent roots, running downward into the loose rock almost perpendicularly, 
around which the sand and fine gravel appeared to be invariably hardened 
into a cemented pipe-like mass. Having tested these tubes with muriatic 
acid, I should not expect them to contain lime, as I once supposed. 
More probabl}^, the potash in the wood combining with the surrounding 
quartzose sand, has given rise — first to a solution, and afterwards to a de- 
position of siliceous particles. 
Much of this district, near Brighton, is covered on the surface by depo- 
sits of shells several inches in thickness, wherein Cardium, Turbo, Trochus. 
Haliotis, and other species having representatives in the isdjaccnt sea, aro 
found in great abundance. In some places, these shelly deposits, being 
mixed up with arenaceous matter and small pebbles, by afterwards par- 
tially decomposing form a soft, easily broken, shelly gravel or conglome- 
rate, interesting to the youn^ geologist, since he can thus readily trace 
every step of the process which changes the loose sand, unconsolidated 
pebbles, and aggregated shells, into a tolerably firm and stony rock of 
highly fossiliferous character. 
The evidence of these shell-beds goes far to show the very recent up- 
heaval of the surrounding district. A little observation will, however, 
reveal traces of more than one phenomenon of this description, together 
