Thomson. — Glacial Action in Otago. 313 



These strife are not to be mistaken for liarrow-marks, often seen on stones 

 where fields are in cultivation. They are always found on the lower surface 

 of the boulder as it lay on the ground bedded for ages, and by which 2>osition 

 alone were the marks preserved, from disintegration. They are never found 

 on the upper surface of the stone, and are only to be sought for by turning 

 over the block. At one of Sidey's fields almost every tenth stone has the ice 

 scores on it, deeply indented in the surface, and which marks it had received in 

 remote ages. Yet there are the marks, as patent and as certain as on the day 

 they wei'e made — a proof of ice action — a proof that this country was once the 

 region of perpetual frost and snow, and unfit for the habitation of man. 



The grooved rock in the Kaikorai Yalley presents another lesson tending 

 to the same conclusion. This rock juts oxit at a sharp turn of the main road, 

 and appears at one time to have ofiered considerable opposition to the 

 descending masses of ice, for over its whole surface grooves, nine inches to a 

 foot in depth, are worn in the direction of the axis of the valley, and which 

 have been preserved from disintegration by having been covered by a layer of 

 clay after the ice action had ceased. 



Thus, according to my limited observation, I have advanced such facts as have 

 occurred to me, proving the ice-bound nature of the surface and shores of this 

 island as it existed in remote ages of this recent geological period. More 

 extended observations may be made by those having more time and opportunity ; 

 but T trust I have said enough. 



While we may admit, then, that much colder temperature than now exists 

 has been proved, so also the converse has to be accepted, though it be not 

 necessaiy to the present argument. In Europe, the existence in prior 

 geological periods of tropical vegetation is abundantly exhibited in the fossil 

 remains of low latitudes, and, as a matter of near interest to us, in the case of 

 one of these fossils the Norfolk Island pine is, in our age, the only remaining 

 and living example. In New Zealand we have a parallel case tending to 

 prove the same fact — the remains and gum of the kauri are found at this end 

 of the islands, while the living tree is only to be found north of Auckland. No 

 doubt, a more comprehensive knowledge of the geology of New Zealand, than 

 I can claim to have, will confirm an alternation of temperature, not once, but 

 for many times. 



With these preliminary observations I may now proceed with the more 

 immediate object of the paper. In looking over some of the topographical 

 maps executed by the officers of the Survey Department, I was struck with 

 the regularly curved beds of the valleys, notwithstanding that the country 

 through which they wandered was of the most rugged and mountainous 

 description. My attention was first drawn to the Manulierikia, a drawing of 

 which is on the table, copied from a sketch which I made on its tirst exploration 



xl 



