574 Transactions. —Geology. 
either way; nor are we justified in ascribing to Tongariro and its adjacent 
volcanoes the origin of the whole of this pumice, until a thorough explora- 
tion of the mountainous Urewera country shall have proved that it did not 
emanate from some nearer source. That volcanic rocks exist somewhere 
in that direction is proved by the finding of volcanic pebbles in the bed of 
the Wairoa River, which must have come down the Hangarou, one of its 
main branches, and which has its source somewhere in the neighbourhood 
of Maungapohatu, a lofty mountain some 20 miles to the north and east of 
Waikaremoana. 
Of other recent formations present there are the river terraces, sand 
dunes, lagoons along the coast, caves in the limestone, and the fine gravel 
along the beach. The course of the Mohaka River presents some fine 
examples of the first. Near its mouth I have counted as many as eleven 
separate and distinct terraces, some high, some of only a few feet. These 
are all cut out of the solid Papa rock, and in the ease of the higher one of 
all (which forms the true valley of the river) this has been spread over with 
a deposit of shingle derived from the slate mountains of the interior, of from 
six to eight feet thick. It forms a plain about ten miles long by a varying 
width of from one to two miles. It is covered thickly with pumice, as 
before mentioned. Its general level is from 200 to 300 fect above the 
present river, which has cut for itself a deep precipitous channel, the sides 
of which afford an excellent section of the various beds through which it 
passes. The terraces of the Wairoa River are not so well developed. There 
is one large one, however, which extends up both the main branches at a 
general height of from 50 to 150 feet above the river level. This is also 
generally covered with pumice, but not to so great an extent as those of 
Mohaka, whilst the recent and lower ones are nearly free from it. Of sand 
dunes there are not many, the coast being generally bold and precipitous. 
They are found at the low narrow neck of land connecting the Mahia 
Peninsula with the main (and which narrow neck, I may here observe, 
would, by a depression of 20 feet, again be submerged, thus making the 
Mahia an island), and also about the Whakeki Lagoon, which owes its 
origin to the banking up of the sand and gravel from the beach. A regular 
gradation may be observed in the sizes of the gravel on the beaches, which 
at Petane is small shingle, but sets smaller and smaller until at Nuhaka it 
has become ground down into coarse sand. 
The caves of the limestone formation are numerous, but I never had 
time to visit them. 
The Natives relate stories of most wonderful caves, grottos, and fissures 
as existing in the Whakapunake Mountain. They also stated that in one 
of these caves, the last of the Moas had his residence, and that their 
