233 
of an island , in the middle of the larger tuff-crater , and is sur- 
rounded either by water or swamp, as at Mt. Richmond, Fort 
Richards and several points South and Southwest from Otahuhu. 
In fact, examples of every gradation may be seen — from the 
simple tuff-crater without any cinder-cone, to those which are en- 
tirely filled up by the cinder-cones. Especially interesting are those 
which may be said to represent the middle state; perhaps the 
most perfect specimen of this kind is the Waitomokia Southwest 
of Otahuhu. No doubt, such forms may partly be explained also 
by a later sinking down, by a sagging of the cinder-cone within 
its tuff-enclosure , by which even cones , that formerly had towered 
high above the tuff-crater, sunk in to their topmost points, some 
of them perhaps disappearing entirely. The destroying influences 
of water and atmosphere have also wrought a change of the ori- 
ginal forms. This may be the case especially with the remark- 
able point of eruption within the very precincts of the city of 
Auckland, upon the half- destroyed tuff- and cinder-cone of which 
the central parts of the city are built. I will give a more detailed 
description of this point. The Wesleyan Church, Mechanics’ Institute, 
the Auckland Hotel and other buildings are built upon a kind of 
terrace, higher by about 40 feet than Queen-street; behind the ter- 
race at a steep angle and almost with a semicircular slope the hill 
rises, upon which the barracks stand, and on the northern and eastern 
slope of which the Governor’s house , St. Paul’s Church and the 
Princes’-street are situated. I consider the terrace to be the central 
point of eruption, or the remains of a sunk cinder-cone. The 
foundations of the buildings are resting there on more or less 
compact masses of cinder and basaltic lava, blocks of which are 
everywhere in the vicinity protruding from the ground. The steep, 
almost semicircular declivity, 200 feet high, however, is to be 
considered as the eastern half of a large tuff-crater, the western 
half of which, beyond Queen-street, is scarcely to be recognized 
by a thin layer of volcanic tuff*, which has been almost entirely 
decomposed into yellow clay. Queen-street intersects the former 
tuff-crater in the direction from North to South. Near Odd Fel- 
