Igneous Rocks.

In the longitudinal zone running parallel to the main axis of the Southern Alps, first alluded to, I found no traces of igneous rocks, but, in the southern portion of the province, in the ranges forming the western banks of the Makaroa river, numerous dykes of igneous rocks, generally of small dimensions only, have been injected into the phyllites. Some of them are melaphyres, often amygdaloidal, which, on the banks of the River Young, near its junction with the Makaroa, can be observed in situ. On the eastern declivities of Castle Hill, near the head of the Makaroa, large blocks of phyllite crossed by dykes of diorite and dioriticporphyry, were lying on the mountain side, having doubtless been brought down from near the summit. In these dykes, angular pieces of phyllite are enclosed. Similar rocks were met with in the upper course of the Haast river, in nearly every affluent coming from the west, so that there is no doubt that the strata belonging to the formation under review have, in the eastern portion of the folds, been broken through by igneous rocks for a long distance.