THE ZooLocist—JuLy, 1875. 4515 
enlargement of pre-existing hollows, such as are found as air- 
bubbles, often of gigantic size, in lava-streams running generally 
parallel to the action of their flow. In this instance, there is no 
doubt that the Moa-bone Point Cave is a pre-existing hollow in a 
doleritic lava-stream, which has been enlarged by the enormous 
power of the dashing waves of the ocean beating here at one time 
furiously against the northern foot of the Peninsula. 
In previous publications (amongst others, ‘ Report on the For- 
mation of the Canterbury Plains, 1864, p. 22 ef seg.), I have shown 
how in post-pliocene times from the material brought down by the 
enormous glacier-torrents, forming huge shingle fans at the foot of 
the glaciers, two bars were thrown across the sea—one to unite the 
northern or Waimakariri-Ashley deposits with the northern slopes, 
another to connect the southern or Rakaia-Ashburton beds of the 
same nature with the southern slopes of Banks Peninsula, behind 
which a huge lake was formed, of which Lake Ellesmere is the last 
remnant. Of the northern bar we can trace the inner or western 
shores through Kaiapoi to the neighbourhood of Woodend. In 
this large fresh-water lagoon (occasionally an estuary basin) the 
Waimakariri, Selwyn, and sometimes the Rakaia, discharged their 
waters, having an outlet near the north-western slopes of Banks 
Peninsula, of which, in going towards Cashmere, the residence of 
Sir Cracroft Wilson, we can easily trace the lines of dunes and 
shingle by which the eastern shore of that lake was formed, being 
in the beginning very narrow, and only gradually, as more and 
more material was added, assuming a greater breadth. Thus, we 
are able to follow the different lines of these earliest-formed beds 
from the neighbourhood of Kaiapoi, where they are comparatively 
narrow, along the eastern boundary of Christchurch to the northern 
foot of the Peninsula, gradually diverging more and more. 
In my former paper, entitled “ Moa and Moa Hunters” * (Trans- 
actions of the New Zealand Institute, vol. iv., p. 89), I have already 
alluded to the fact that the ovens of the moa-hunters were confined 
to the inner lines of these dunes, and a further close examination 
of the district between Christchurch and New Brighton has con- 
firmed fully my former more local observations. Thus it is evident 
that when the former inhabitants of this part of New Zealand existed 
principally upon the chase of the moa, the sand-dunes had scarcely 
* T trust on a future occasion to be favoured with a copy of this paper also for 
publication in the ‘ Zoologist.—E. N. 
