1848.]_MANTELL ON FOSSIL REMAINS FROM NEW ZEALAND. 231 
With the view of elucidating these remarks, and the inferences I 
shall presently venture to suggest, I will here concisely describe the 
geological structure of New Zealand, on the authority of Dr. Dieffen- 
bach. This country, which is situated between 30 and 50 degrees of 
south latitude, forms a group of mountainous islands nearly as large 
as England and Wales. Its geological structure is with difficulty de- 
termined, owing to the primeeval forests which frmge the coast ; and 
where these have been destroyed, by impenetrable thickets of escu- 
lent fern. The fundamental rock is everywhere clay-slate, which is 
frequently traversed by greenstone dykes, as at Port Nicholson, 
Queen Charlotte’s Sound, and Cloudy Bay. On the banks of the 
rivers Eritonga, Waibo, and along some parts of the sea-coast, there. 
are horizontal terraces of boulders of trap-rocks 50 feet high. An- 
thracite coal crops out in the harbour of Wangarua; and there is a 
seam of the same mineral intercalated in the hard grey sandstone on 
the east coast of the Northern Island. On the west coast of the 
same, the limestone contains a few shells, as pecten, ostrea, terebratula, 
and an Hehinus spatangus. The coasts are in many places fringed 
with recent horizontal sediments, consisting of loam with fragments 
of wood and fern, &c. The small rocky islands of trachyte off the coast 
of the Northern Island also bear marks of wave-action to the height 
of 100 feet above the present sea-level. In the interior of the 
Northern Island there is a lofty central group of volcanic mountains, 
some of the volcanos being still in activity : the ancient lava-streams 
appear to have been principally erupted from the base of the craters. 
The highest mountains are Tongariro, which is 6000 feet, and Mount 
Egmont, 9000 feet high. The loftiest summits are covered with per- 
petual snow. There are many lakes, which appear to occupy ancient 
craters*. 
The occurrence of terraces of loam and gravel of comparatively re- 
cent date, at an elevation of from 50 to 100 feet above the sea, along 
the coasts of New Zealand, prove that a considerable change in the 
relative level of the land and water has taken place since those ter- 
races were deposited, and at no very remote period. The present 
rivers of the country are described as now cutting deeply the beds of 
volcanic detritus and silt im which the birds’ bones are contained ; 
and the latter are in some places covered by marine and freshwater 
deposits. The facts adduced appear to me confirmative of the opinion 
advanced by Mr. Colenso (in 1842), that the true situation of the 
ossiferous deposit is beneath the surface-soil of the fluviatile beds 
formed by the present rivers. In the more elevated regions the bone- 
deposit consists of pure volcanic sand and detritus; while in the low 
districts and along the coasts it is composed of fluviatile mud or silt, 
which in many places is covered by modern beds of shingle and 
ravel. 
: II. Description of Mr. Walter Mantell’s Collection.—I will now 
describe in general terms the most interesting specimens in the 
collection formed by my son; the anatomical details, and the im- 
portant physiological inferences resulting therefrom, will be laid 
* British Association Reports for 1845. 
