98 Transactions. 



The sharp scarps of many of the rhyolite hills do not indicate 

 the action of faults, but are due to erosion. 



The sequence of eruptive rocks is suggested. 



Note. — Specimens lately collected by Mr. R. Speight show that 

 hornblende-andesite with much hypersthene occurs on the north slope of 

 Ruapehu, and also on A Tama. This confirms Hutton's statement. 

 The rock resembles that of Egmont in some respects, but must be 

 scantily distributed on Ruapehu. 



Since the above was in type I have received specimens of rock from 

 the Patua Range, north of Mount Egmont, from Mr. N. Cochrane, and 

 others from near Albatross Head, Kawhia, from Mr. R. Browne. In 

 both instances the rocks are similar to those of Mount Egmont, except 

 that pyroxene is entirely absent. 



EXPLANATION OF PLATE XIII. 



1. Recent and Pleistocene. Sands, gravels, and pumice. 



2. Cainozoic. Chiefly Miocene limestones and marls. 



3. Mesozoic. Chiefly Triassic shales and sandstones. 



4. Rhyolite. Eruption began in Miocene. 



5. Hornblende-andesite, Mount Egmont ; dacite, Tauhara. 



6. Andesites of Cape Colville. Eruption in Miocene. 



7. Manukau breccia. Hypersthene-andesites, Miocene. 



8. Volcanoes of rhyolite plateau. Hypersthene-andesites, Upper Pliocene 



to Recent. 



9. Dolerite of Pirongia and Karioi (Miocene ?). 



10. Basanites. Waikato, Auckland, &c. 



11. Older basalts of Kerikeri. 



12. Diorites and gabbros. Age uncertain. 



Note. — The map, Plate XIII, is largely based on the work of McKay, 

 Park, and Cox so far as the boundaries of the sedimentary and volcanic 

 rocks are concerned. The author alone is responsible for the boundaries 

 of the different divisions of volcanic rocks. 



Art. VI. — Fossils from Kakanui. 



By J. Allan Thomson, B.Sc. 



Communicated by G. M. Thomson. 



\Rnid In ■■fori tin Otago Institute, 8th October, 1907.] 



Plate XIV. 



The fossils treated of below were collected in 1903, when the 

 author was working at the gem gravels of Kakanui. After a 

 preliminary determination of the species, they were submitted 

 to Captain Hutton, and agreement was reached as to the names. 

 He recommended that the generic names in Zittel's " Text- 

 book of Palaeontology" (translation, C. R. Eastman, 1900) 



