Speight. — The Geology of Banks Peninsula. 365 



Art. XXVI. — The Geology of Banks Peninsula.* 



By R. Speight, M.Sc, F.G.S., Curator of Canterbury Museum. 



[Read before the Philosophical Institute of Canterbury, 3rd November, 1915; received by 

 Editors, 30th December, 191<> ; issued separately, 5th November 1M7.] 



Plates XXIV-XXVI. 



Table of Contents. 



A. Introductory. 



B. General Topography of the Area. 



1. Lyttelton Harbour and Neighbourhood. 



2. Akaroa Harbour and Neighbourhood. 



3. Little River Valley, Kaituna Valley, &c. 



C. Geological History. 



1. Trias- Jura Greywackes and Slates at Gebbie's Pass and Head of Lyttelton 



Harbour ; Occurrence of Sandstone at Governor's Bay, Little Quail 

 Island, Charteris Bay. 



2. First Volcanic Phase : Rhyolites — their Occurrence at Gebbie's Pass, Head 



of the Bay, Charteris Day, and Quail Island. 



3. Second Volcanic Phase. 



(a.) Lyttelton: Extrusion of Andesitic and Normal Basalts; the Dyke 

 System. 



(6.) Akaroa; Basic Flows, Dykes, Syenite. 



(c.) Little River Valley : Not a Separate Volcano. 

 ■4. Third Volcanic Phase. 



(a.) Mount Herbert Volcano. 



(6.) Mounts Fitzgerald and Sinclair to be assigned to Second Phase. 

 5. Fourth Volcanic Phase. 



Quail Island. 

 t>. Post-volcanic History. 



(a.) Evidence of Greater Elevation, followed by Depression and Slight 

 Recent Rise. 



(b.) Results of Erosion and the Formation of Calderas. 



A. INTRODUCTORY. 



Banks Peninsula as a geological locality has attracted considerable atten- 

 tion at various times, but no detailed account of its geological features 

 has appeared since Haast published in 1879 his Geology of Canterbury and 

 Westland. In this work he summarizes the results of his observations and 

 investigations as Provincial Geologist, reports of which he had furnished to 

 the Provincial Government from time to time, and which were published in 

 its Gazettes. A petrological account of the recks occurring in the Lyttelton 

 Tunnel, based on collections made by Haast while it was being con- 

 structed, appeared in Filhol's Mission de Vile Campbell, which was issued 

 in Paris in 1885, this containing as well a summary of the geological 

 history of New Zealand. Since then various petrological papers have 

 been published dealing with the rocks of the district, among which may 

 be mentioned " The Microscopical Investigation of some Eruptive Rocks 

 from Banks Peninsula, New Zealand," by B. Kolenko (Neues Jahrb. f. 

 Min., Geol., Pal., 1885, Band 1, p. 1; translation published in N.Z. 

 Journ. of Science, vol. 11, 1885, p. 548), and " The Igneous Rocks of New 

 Zealand," by Hutton (Journ. and Proc. Roy. Soc. N.S.W., 1889), containing 

 reference to many rocks from the peninsula ; while the following papers 

 have appeared in the Transactions of the Neiv Zealand Institute : " The 



* This paper is intended to be introductory to one dealing with the petrology of 

 the district, which will be submitted at a later date. 



