110 
THE GEOLOGIST. 
Note on a Progressive Change in the Form of the Earth. — 
If it be assumed that tJie eartli has cooled to its ])resent temperature from 
a state of incandescence, it will follow that its form is subject to a slow 
progressive change. Let A C B D be the spheroid of equilibrium at any 
epoch, the form of this 
of rotation. If either 
C 
spneroid depends on its magnitude and the velocity 
of these changes, the form will change. Now let 
the spheroid A C B D contract, by cooling, 
to the spheroid a c h cl, whose surface may 
be considered as parallel to A C B D ; when 
the amount of contraction is small, therefore 
B h is equal to C c. If these equals bo taken 
from both terms of the ratio O B : O C that 
ratio will be increased ; therefore 0/^:0^* 
is greater than O B : O C ; that is, the equa- 
torial diameter has a greater ratio to the 
polar diameter than it had before the con- 
traction took place. The effect of this is equivalent to a constant accu- 
mulation of matter at the equator in excess of what is due to the velocity 
of rotation. This excess could never attain to any considerable magnitude 
so long as the earth was iu a fluid state, as the change would take place 
2')er gmdum from the old to the new spheroidal form of equilibrium ; but 
when the external crust became suflficiently rigid to oppose resistance to 
the change of form, the alteration would take place per saltum at the 
w^eakest points. This is probably worthy of the attention of those who have 
the necessary qualifications for discussing mathematically the difficult but 
intensely interesting subject — the physical causes of geological phenomena. 
To those who feel a difficulty in understanding how contraction towards 
the centre can produce upheavals y>'o;» the centre, I recommend the fol- 
lowing experiment. Fuse a bead of carbonate of soda in the blowpipe 
flame. Dip the bead into a little powder of silex and fuse agam. Watcli 
the cooling through a magnifier. Conical hills start up and mountain- 
chains are formed as if by magic. The experiment may be repeated an\' 
number of times with the same bead, which proves that the elevations arc 
not caused by escaping carbonic acid gas, but by the contraction of the ex 
ternal cooling surface on the .internal fluid mass. — G. H. 
Mammalian Eemains in the Hampshire Gravel. — Sir, — In the num^ 
ber of your periodical for November last, p. 427, you were good enough td 
publish a communication from me, from which it might be inferred that 
my inquiries for animal remains, in the gravel deposits of this neighbour 
hood, had been fruitless. 
I have since, however, by inquiring of gravel-diggers, been made ac 
quainted with, and have to-day seen, a molar tooth of an elephant from the 
gravel at Swathling, which is a village about three miles east of this town 
This is the only instance of the kind in this neighbourhood with which ] 
am acquainted ; but I remember meeting somewhere with the mention o 
the existence of mammalian remains in the gravel at a locality at the bacK 
of the Isle of Wight : perhaps you might be able to tell me if there ar^ 
any other such fossil-bearing spots, in the gravel, recorded as existing it 
the county of Hampshire P ' 
I was likewise shown to-day a bunch of sea (P) shells from the gravel 
also from the neighbourhood of iSwatlding, but from a different locality t< 
where the first-mentioned fossil was found. W. T. Nicolls. 
Southampton, Fehraarij U, 1863. 
New Species of Fish from the Crag. — Dear Sir, — I believe tha 
up to the present time the remains of Placoid fish only have been found ii 
