456 Transactions.-— Geology. 



that the loess in China could only be of sub-aerial origin, de- 

 posited by apnais, which at the present time are still at work in 

 forming that rock. Atmospheric currents, together with the 

 growth of gi'ass and other vegetation, during an untold number 

 of years, are the principal agencies by which the loess has been 

 deposited. In the first instance, rain water, running down the 

 more or less steep slopes of the country, carries with it fine 

 particles, which are partly retained by the grass or amongst its 

 roots ; whilst the wind, blowing across the land, takes up a 

 great amount of fine sediment, afterw^ards also partly caught 

 and retained by the grass. However, a third and most import- 

 ant agent is to be found in the roots of the plants themselves 

 decaying, and thus raising the ground. There is a peculiar 

 vertical capillary texture observable in the true loess, deriving, doubt- 

 less, its origin from the decaying of numberless rootlets during 

 many past generations of grasses." Dr. Haast goes on to state, 

 " during the Great Glacier Period of New Zealand, beginning 

 towards the end of the pliocene and ending in the post-pliocene 

 period, during quaternary and recent times, the /oe'ss-beds have 

 gone on accumulating steadily so as to reach such a considerable 

 thickness, as we find them, amongst other localities, as the 

 lower slopes of Banks Peninsula, and on the Timaru plateau." 



This view has been opposed by Professor Hutton, who, in an 

 article on the silt deposit at Lyttelton, laid before the Philo- 

 sophical Institute of Canterbury,* clearly shows that those 

 deposits do not belong to the loess formation. After weighing 

 all the evidence he could obtain, he arrives at the conclusion 

 " that the evidence in favour of the marine origin of this deposit 

 preponderates enormously over the evidence in favour of its 

 sub-aerial origin," including in this judgment the Timaru 

 formation. Not having seen much of Banks Peninsula, I am 

 unable to make any personal remarks on the silt formation 

 there ; but with Timaru it is different, as having been resident 

 there for some time, I have had the opportunity to obtain such 

 information as makes me differ from Dr. von Haast as well as 

 from Professor Hutton. 



The Timaru Downs are situated to the south of the Canter- 

 bury Plains ; they are about six miles broad, and extend inland 

 from the sea about ten miles. They consist of gentle undulating 

 country, well adapted for agriculture. The structure of these 

 rolling downs is very peculiar. It is very evident, from abun- 

 dance of data, that the Canterbury Plains at one time extended 

 all along where these downs now exist, and that actually the 

 plains are there at present (beneath), and that the downs have 

 been built on the plains. The plams beneath the downs have 

 been covered over with beds of dolorite or basalt, and over the 



• " Trans. N.Z. Inst.," vol. xv., p. 411. 



