Smita.—Geology of Northern Portion of Hawke Bay. 573 
all the particles are waterworn or abraded, and that many of them are too 
large to be carried by an ordinary wind, being sometimes as large as walnuts, 
though the average size would be about an eighth of an inch in diameter. 
The only other hypothesis which would account for the presence of pumice 
over such an extent of country is, that it has been carried into its present 
position by water. No doubt many of the extensive pumice drifts of the 
North Island do owe their origin to that cause, notably the pumice plains 
of Kaingaroa, near Taupo, which in places are regularly stratified, and often 
contain the trunks of trees, lying in a horizontal position, converted into 
charcoal; but there is a great deal of difference between the pumice 
deposits of Taupo, the Waikato, and the inland portion of Taranaki 
and those of Northern Hawke Bay. The former invariably occupy level 
plains or depressions, which no doubt were at one time lakes. To my 
mind, a deposit of a light substance like pumice, which ordinarily floats on 
the surface of the water, is only possible in enclosed sheets of water, which 
would not allow of its escape. If it once reached the open sea it would be 
carried far and wide by the winds and currents. There is one thing, how- 
ever, which should not be forgotten, and that is, that the enclosed air, to 
which pumice owes its buoyancy, might under pressure be driven out, in 
which case, of course, it would become water-logged and sink, and would 
then form regular aqueous deposits like sand orclay. That such deposits 
are sometimes met with, I think every one must allow who has seen the 
Kaingaroa Plains, or the beds of coarse white sandstone found near the 
Miranda Redoubt, which is, I think, without doubt, formed of coarse pumice 
sand, consolidated under pressure; and the deep pumice strata found in the 
Tauranga District. 
I observe in the last volume of the ** Transactions of the New Zealand 
Institute," that Mr. J. C. Crawford, of Wellington, in his paper on “ The 
Old Lake System of New Zealand," has touched upon this subject, and comes 
to the conelusion that the great central pumice drifts are lake deposits. In 
this I entirely concur, as far as relates to the country described by Mr. 
Crawford, but I think that the lake theory cannot be applied in this distriet. 
The large extent, and great height of the country over which the pumice is 
scattered precludes the idea that it is entirely due to the action of water, 
whilst the fact that the thickest deposit seems to be confined (in this district 
at least), to the northward of a line drawn in a true east direction from 
Ruapehu, would add force to the argument, that it was spread out by 
the prevailing westerly winds; and the water-worn appearance may be ex- 
plieable on the supposition that it is due either to decomposition or to the 
attrition of the particles as they were ejected from the voleano. The 
amount of evidence, however, is not sufficient to come to a conclusion 
