446 JOURNAL OF SCIENCE. 
stone ash, we may provisionally consider them all as belonging to the 
upper parts of the Maitai system. 
Of eruptive rocks belonging to the Hokanui system, we have 
evidence near the Hurunui Plains, where the Mandamus River cuts 
through a volcanic region in which ash-beds and lava streams are 
interbedded with slates containing plant remains. In the South Island 
extensive eruptions of quartz, felsites, rhyolites, and dolerites—the 
latter often altered into melaphyres—-took place along the western 
margin of the Canterbury Plains, at the Malvern Hills, Alford Forest, 
Mt. Innes, and Gawler Downs, during the deposition of the older rocks 
belonging to the Waipara system. Quartz-felsites of the same character 
form the base of the western portion of the volcanic system of Banks 
Peninsula. These quartz-felsites are overlaid by basalts, which are 
again pierced by dykes of andesite, trachyte, and rhyolite. There is at 
present no evidence as to the age of these andesites and trachytes, but 
it would be more in accordance with von Richthofen’s law to suppose 
that they have no connection with the felsites, but belong to much later 
eruptions, probably of the Oamaru system. A remarkable compact 
siliceous rock, generally of a green or purple colour, called Palla by Dr. 
von Haast—a name employed by the Austrian Geological Survey— 
occurs at the Gawler Downs and Mt. Alford. On the west coast of 
the South Island basic volcanic rocks occur at Paringa and other places 
south of Bruce Bay, which may belong to this system or to the next. 
In the North Island volcanic rocks, said to belong to the Waipara 
system, occur on the east coast of Wellington, at Red Island, south of 
Cape Kidnappers. 
In the South Island dolerites and basalts are finterbedded with 
sedimentary rocks of the Oamaru system, at Oamaru, at Culverden, and 
at Pahau, on the north side of the Huranui Plains. In all these places 
the sedimentary rocks can be shewn to have been disturbed after the 
voleanic action had ceased. The andesites and perhaps even the 
dolerites of Dunedin Peninsula belong to this system, also a large part 
of Banks Peninsula. At Limestone Bluff and the Two Brothers, on 
the south branch of the Ashburton River, a “ Palagonite tuff” occurs, 
which while agreeing well in ultimate analysis with specimens obtained 
in other countries, does not appear to contain any palagonite. In the 
Trelissick basin, on the Waimakariri, beds of volcanic tuff overlie and 
underlie a limestone which is thought to be the equivalent of the 
Ototara stone. 
According to Dr. von Haast, whose extensive and excellent 
researches on the structure of Banks Peninsula I can in great part 
confirm, there have been here—in addition to the quartz-felsites of the 
Waipara system already mentioned—three other periods of activity. 
To the first of these belong the calderas of Lyttelton, Little River, and 
Akaroa, in which the lava streams are chiefly basaltic with some 
andesites,* cut by dykes chiefly of andesite, but occasionally of trachyte 
basalt, and at least one of rhyolite. To the second period belong Mt. | 
Herbert and Mt. Sinclair, which are formed of basalts with some 
andesites, but without any visible dykes. To the third period belongs 
the formation of Quail Island, which is, again, composed of basalts with 
* For the knowledge that these rocks are andesites, I am indebted to Prof. 
G. H. F. Ulrich. 
