120 Lecture on the Geology of [No. 9, new series. 



Auckland, by Colonel Mould, who has kindly forwarded me a 

 copy of his tables. 



I have also obtained photographic and other views of great inter- 

 est, many of which were taken by the gentlemen who accompani- 

 ed me on the expedition for this purpose ; and a large number of 

 exceedingly valuable sketches have been contributed by the ta- 

 lented pencil of our President, Mr. C. Heaphy, for future publica- 

 tion in a 'geological Atlas. Many of these are decorating the 

 walls and others are lying on the table, and I shall be happy to 

 show them to any ladies and gentlemen who may feel an interest 

 in seeing them, at the conclusion of the lecture. 



My collections have been growing from day to day, and include 

 specimens of great interest in most branches of Natural History. 

 I owe a great deal to the indefatigable zeal of my friend and fel- 

 low-traveller, Mr. J. Haast, who assisted me in collecting during 

 our expedition. I am also much indebted to Mr. J. Crawford at 

 Wellington, Mr. A. S. Atkinson of Taranaki, Mr. Triphook of 

 Hawke's Bay, Mr. H. T. Kemp of the Bay of Islands, to the Mis- 

 sionaries, and to almost innumerable friends in Auckland. 

 Preliminary Remarks. 



I cannot suppose that all my audience are acquainted with the 

 first principles of Geology. I shall therefore be under the neces- 

 sity, in order to make my report intelligible, of prefacing a few 

 remarks upon the chief divisions of the Geological formations. 



The various rocks, soils, and minerals, which occur upon the 

 surface of the earth, or at various depths beneath it — in one word, 

 the materials of the "earth's crust" — are classified, in the first 

 place, with reference to their different origin, or, in other words, 

 with reference to the different circumstances and causes by which 

 they have been produced. They are divided into four great classes 

 — Plutonic, Metamorphic, Aqueous, and Volcanic rocks. Another 

 mode of classification is with reference to their age — that is, to the 

 comparative periods of their formation. Those divisions will be 

 easily understood. 



The Plutonic rocks comprehend all the granites, syenites, por- 

 phyries, diorites — rocks which agree in being highly crystalline, 

 unstratified, and destitute of organic remains — which are consi- 



