GEOLOGY OF NE^Y ZEALAND. 215 



Eetjptive Eocks. 



The oldest of our eruptive rocks are found in the Manapoiiri 

 System at the West-Coast Sounds, in the form of dykes of white 

 granite, minette, eurite, &c. They do not penetrate any higher, and 

 no eruptive rocks have yet been noticed belonging to the Tdlccika 

 System. 



Matted System. — The pink granite found at Preservation Inlet, as 

 well as the granites along the ge-anticlinal axis through Westland 

 and Nelson, have penetrated some of the rocks of the Maitai System, 

 but are found as rolled fragments in the rocks of the Kaihiku Series 

 at the base of the Hokaniii System*. Their eruption therefore must 

 have taken place some time during the deposition of the Maitai 

 System, and they are probably contemporaneous vrith the dykes of 

 syenite, diorite, olivine rocks, and serpentines as well as the green- 

 stone ashes found in various localities in the Maitai System. 



Holcanui System. — There is evidence of eruptive rocks belonging 

 to this date near the Hurinui Plains, where the river Mandamus 

 cuts through a volcanic region in which ash-beds and lava-streams 

 are interbedded with slates containing remains of plants f. 



Waipcira System. — In the South Island extensive eruptions of 

 white or light-coloured quartz-rhyolites and dolerites, the latter 

 now often altered into melaphyres, took place along the western 

 margin of the Canterbury plains at the Malvern Hills, Alford Porest, 

 Mt. Somers, and Gawler Downs, during the deposition of the older 

 rocks belonging to this system t- Quartz-rhyolites of the same 

 character form the base of the western portion of Banks's Peninsula, 

 but the rest of this volcanic system is of later date. 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 the Waipara System 

 or to the next §. In the North Island volcanic rocks, said to be of 

 this age, occur on the east coast of Wellington, at Eed Island, south 

 of Cape Kidnappers |j, and perhaps near Castle Point ^. 



Oamaru System. — In the South Island basaltic rocks are inter- 

 bedded with sedimentary rocks of this system at Oamaru Cape**; 

 atCulverden, and at Pahauffon the north side of the Hurinui Plains. 

 In the Trelissick basin on the Waimakariri, beds of volcanic tuff 

 overhe and underlie a limestone considered to be the equivalent of 

 the Ototara stone tt- At Limestone Bluff and at the Two Brothers, 

 on the south branch of the Eiver Ashburton, a " Palagonite tuff" §§ 



* Cox, Hep. Geol. Surv. 1877-78, p. 47. 



t Haast, Eep. Geol. Surv. 1870-71, p. 46, and Hutton, Rep. Geol. Surv. 

 1873-74, p. 34. 



I Haast, Eep. Geol. Surv. 1871-72, p. 12, and I. c. 1873-74, p. 7 ; Hutton, 

 Eep. Geol. Surv. 1873-74, p. 40 ; Daintree, Trans. IN". Z. Institute, vii. p 458. 



§ Cox, Eep. Geol. Surv. 1874-76, p. 8 ; Haast, Geol. Canterbury, p. 302. 



II M'^Kay, Eep. Geol. Surv. 1874-76, p. 45. 



^ M'^Kay, I. c. 1874-76, p. 59. ** Geology of Otago, p. 55. 



ft Eep. Geol. Surv. 1873-74, p. 46. 

 i^ M'^Kay, Eep. Geol. Surv. 1879-80, p. 60. 

 §§ Haast, Geology of Canterbury, p. 313. 



