COCKA.YNE. — Plants of Chatham Island. 219 



Geology. 



Not very much is known about the geology of Chatham 

 Island. Mr. Travers collected rock specimens and a few 

 fossils. From these specimens and from notes supplied by 

 Mr. Travers Sir Julius von Haast published the only paper 

 (a very short one, occupying a page and a half) which, so 

 far as I am aware, has appeared on the geology of the island.* 

 Captain F. W. Hutton, F.R.S., has also examined Mr. Tra- 

 vers's specimens, and he tells me that he agrees with the 

 main conclusions in Haast's paper — namely, that the Chat- 

 ham Islands first emerged from the ocean during some 

 portion of the Tertiary period. 



The following is abstracted from Haast's paper (23) : 

 " The, principal island is of volcanic origin, and consists 

 chiefly of basaltic and doleritic rocks and tufas." " Several 

 cones" with a crater-like character show in the different 

 centres of eruption, whilst around them and extending from 

 one to the other marine sands have formed barriers enclos- 

 ing tracts of low land favourable for the formation of peat 

 swamps." I may here point out that, as probably the islands 

 have extended over a much wider area than is now the case, 

 these sand barriers must be of comparatively recent origin, 

 while also these tracts of low land are in the north and not 

 in the south of the island, which also contains most exten- 

 sive deposits of peat. " The oldest rocks visible occur near 

 Kaingaroa, and consist of micaceous clay slates, silky and 

 of a pale-grey colour." These rocks, Captain Hutton tells 

 me, must be a portion of an ancient rocky platform from 

 which the new volcanic islands arose. " Some beds of lime- 

 stone fringe the south-western shores of that lagoon " — Te 

 Whanga. Haast concludes, "Thus clear evidence is offered 

 to us that in an early part of the Tertiary period volcanic 

 action took place in this part of the Pacific Ocean, and, 

 although we meet on the main island some signs of the 

 existence of old sedimentary rocks, there is no doubt that 

 these volcanic eruptions gave birth to this archipelago." 

 Haast also mentions the occurrence of lignite beds overlaid 

 by limestone on Pitt Island, and Mr. Florence (18) calls at- 

 tention to the occurrence of lignite in the north of Chatham 

 Island. 



Climate. 



Meteorological observations have been taken for a number 

 of years by Messrs. Shand and Cox in the neighbourhood of 

 Waitangi, the thermometers being kept in a screen standing 

 on the grassy slope facing south-east in front of Mr. Cox's 



* See TraDS. N.Z. Inst., vol. ii., art. xliii. : " NotiS on the Geology of 

 the Outlying Islands of New Zealand" (including Cnatham Inlands), 

 v. 183, by J. Hector.— [Ed.] 



