CHAP. XXI.] 
NEW ZEALAND. 
443 
The geological structure of these islands has a decidedly 
continental character. Ancient sedimentary rocks, granite, 
and modern volcanic formations abound ; gold, silver, copper, 
tin, iron, and coal are plentiful ; and there are also some con- 
siderable deposits of early or late Tertiary age. The Secondary 
rocks alone are very scantily developed, and such fragments as 
exist are chiefly of Cretaceous age, often not clearly separated 
from the succeeding Eocene beds. 
MAP SHOWING DEPTHS OF SEA AROUND AUSTRALIA AND NEW ZEALAND. 
The light tint indicates a depth of less than 1,000 fathoms. 
The dark tint ,, „ more than 1,000 fathoms. 
The position of New Zealand, in the great Southern Ocean, 
about 1,200 miles distant from the Australian continent, is very 
isolated. It is surrounded by a moderately deep ocean ; but 
the form of the sea-bottom is peculiar, and may help us in the 
solution of some of the anomalies presented by its living pro- 
ductions. The line of 200 fathoms encloses the two islands 
and extends their area considerably ; but the 1,000-fathom 
line, which indicates the land-area that would be produced if 
