330 
After the writer had spent some time on the samples he found that, to 
obtain a good idea of the full extent of the Tertiary beds in this locality, it 
would be necessary to deepen a bore ; but since re-opening an old bore 
would have been a matter of great expense, it was arranged that the last bore, 
then in operation, should be carried to a greater depth. This was done, with 
the final result that operations had to be suspended on reaching a stratum 
of black flint; but not before the comparatively great depth of 600 feet 
had been reached. The last stratum met with, being of a hard, cherty nature, 
had a serious effect on the connecting rods of the percussion drill. * 1 
4. NOTES ON THE TREATMENT OF THE MATERIAL FROM THE 
BORES. 
The first batch of material was sent to the National Museum from the 
Hon. the Minister for Agriculture (per Mr. A. S. Kenyon) on 26th August, 1908. 
The work of washing, sorting and determining specimens, and of describing the 
material in detail, has occupied a large proportion of my official and private 
time during these past six years; and I would here take the opportunity 
of expressing my thanks to Mr. C. J. Gabriel for his valuable collaborative 
work on the mollusca, and to Mr. R. A. Kebie of the Geological Survey for 
general assistance. 
The samples as received were ail carefully packed in tins or boxes, so 
that no risk of admixture in transit could occur. The superficial deposits, 
such as the Pleistocene sands, were examined both in the natural and 
washed condition, by means of low and high power magnification, and the 
characters of each sample noted. The superficial and concretionary limestones 
were sliced and examined microscopically, in order to ascertain their origin, 
whether organic or chemical. The estuarine muds beneath the superficial 
accumulations of sand and gravel were carefully washed, and both the fine 
and the coarser material examined for organic remains. The foraminifera 
and echinus spines, being usually so minute, were found in the finest of these 
washings ; the former represented by starved or dwarfed shells of species 
which attain larger dimensions when in purer marine habitats. 
The shelly clays, greensands and muds of the Kaiimnan series downwards, 
were carefully washed ; and in the case of small samples no fine material 
was allowed to escape before being examined. Several samples of the 
borings were obtained in such large quantity 2 that the main portion had to 
be washed through a sieve of 40 meshes to the lineal inch ; a smaller portion 
being treated for finer washings, which invariably contained examples of the 
minute Crustacea and foraminifera. The microzoa last-named, which often 
gave interesting data as to depth of sea-bottom when living, as well as climatic 
and other conditions, were generally found in siftings between the 40 to 90 
to an inch mesh. The mollusca were generally obtained in siftings retained 
by the sieve having a mesh of 90 to the inch. 
To prevent injury to the most delicate shells by undue trituration, the 
process of washing these fossiliferous sediments was conducted as follows :— 
The lumps of clay, &c., after being slowly dried, were dropped into a dish of 
water and allowed to disintegrate thoroughly. The soft material was then 
poured into a deep basin and rapidly swirled, and after a lapse of about 
30 seconds the suspended mud was poured off ; then swirled round with very 
little water, and again filled with water and the suspended matter poured 
away. This process was repeated until the residuum consisted mainly of shells 
and comminuted rock or sand-grains, when the material was dried and sifted. 
1 The foreman in charge, Mr. Scarce, writes under date 29th August, 19C9:—“The jar on the rods 
when jumping at that depth (600 feet) is very severe, and you run a big risk of breaking them ; as it was 
ome ol our 10(13 llie lasl llme we h a(1 them down. It would need a diamond drill to get past the 
600 feet. 
i 3 h? r ® xam P le > T 0I : e ^°- 6 a t 114 M.50 feet was represented by about half a hundredweight of blue 
fpyy' t! } s Vy s ' toe coarse material from this sample was sorted, and the fossiliferous contents 
mentihed, the liner material being examined in much smaller quantity, an ounce or so of the washings 
sufficing to give an average idea of the character of the included microzoa. 
