THE GEOLOGY OP NEW ZEALAND. 
461 
land. In the north, the basis is whin, above which is an 
ochreous clay, containing bright particles of magnetic iron, 
which abounds from the North Cape to the Bay of Islands ; 
it is heaped np on the shores in hillocks of several feet in 
height ; as it has been found to make the best steel from its 
containing so much nickel, it must eventually prove a valu- 
able article of commerce ; steatite is also common, limestone 
shows itself in various localities, and when it comes in con- 
tact with whin, it is seen in apparently half-melted lumps 
in the midst of that rock, mixed with cinders and pieces 
of felspar; in other parts it assumes an amygdaloid form. 
Another line of limestone appears at Mokau, a third at 
LIMESTONE CAVE NEAR THE MOKAU, AT PUKEMAPAU. 
Waiapu, near the East Cape, apparently in parallel ranges. 
These are nearly destitute of fossils, but generally partake 
more of the purity of marble, although the surface rock 
contains many particles of clay stone gravel ; at Mokau 
there are numerous caves, in some of which the bones of the 
Moa have been discovered,* at Wangaroa gneiss forms the 
* About a mile from Pukemapau is a large cave in the limestone range, 
which is here first met with, it is called Tanaure-ure ; it has a large lofty 
entrance, with a native Fuschia growing at its mouth, bearing a more delicate 
flower than that of the ordinary kind ; huge masses of stalactite hang pendant 
from the roof, and, further in, we perceived a chasm, which, when a stone was 
thrown, told us there was water at the bottom ; by the aid of a candle, we found 
our way down, when we came to a fine crystal stream, about a foot or so deep, 
