HuTTOX. — Oil the Eru2)tive Hocks of the Bluff Peninsula. 353 



are found resting on similar limestones and clays, were de- 

 posited, the former at the commencement of the Pliocene 

 period, the latter at the commencement of the Pleistocene, as 

 stated by the Geological Survey ? Such a classification is 

 contrary to every geological fact in this district, and it opens 

 up difficulties which cannot be harmonized either by the aid of 

 stratigi'aphical or paleeontological evidence. Mr. McKay, by 

 a single stroke of his pen, removed the Kidnapper con- 

 glomerates from resting conformably upon rocks classed as 

 Upper Miocene, and as passing underneath the Scinde Island 

 lin.iestones, to an unconformability, as of Pleistocene age, and, 

 of course, much younger than the Napier limestones. Had a 

 similar course been adopted with regard to the Kaiwaka and 

 Pohui conglomerates and sands, which, curiously, Mr. McKay 

 first classed with the Kidnapper conglomerates, the altera- 

 tion would have enabled the rocks of this district to be read 

 without difficulty. As remarked at the outset, the official 

 report of the Geological Department is full of interest, and had 

 the Kidnapper conglomerates, together with the Kaiwaka and 

 Pohui beds, been simply removed from Upper Miocene to Lower 

 Pleistocene, this paper would not have been written.* 



Am. XXXV. — Note on the Eruptive Bochs of the Bluf 

 Pe ninsn la , So u th land. 



By Professor F. W. Hutton. 



[Read before the Philosophical Institute of Cantcrbinij, 7th August, 1890.] 



The structure of the Bluff Peninsula has been lately described 

 by Mr. James Park in a report to the Director of the Geo- 

 logical Survey of New Zealand.! It is composed partly of 

 sedimentary sandstones and slates, which are referred by Mr. 

 Park to the Te Anau series, from lithological characters, and 

 partly of eruptive rocks which have usually been called 

 syenites.]; There are also diabasic-ash breccias, which, as Mr. 

 Park points out, prove that volcanic activity was exhibited 

 during the period of deposition of the sandstones. In fact, 

 Bluff Hill is the stump of an old volcano. 



* See map of the district. Trans., vol. xx., pi. xviii. 



t "Eeports of Geological Explorations," 1887-88, p. 72, \\ith map and 

 sections. 



I Dr. C. Forbes, Quar. Jour. Geol. Soc, vol. li., 1855, p. 522 ; Hector, in 

 Otago Provincial Gov. Gazette, 5th November, 18G3 ; Hutton, Eeports 

 Geol. Expl., 1871-72, p. 102; Geology of Otago, Dunedin, 1875, p. 41; 

 Hamilton, Trans. N.Z. Inst., vol. xix., p. 452. 

 23 



