Oliver. — Vegetation of the Kermadec Islands. 123 



Two species hitherto incorrectly iudentified, owing to the imperfect nature 

 of the specimens, I am now able to name, — 



Dryopteris glabella (A. Cunn), C. Chr. = Nephrodium decompositum, 

 Hook, f., Jour. Linn. Soc. (Bot.), vol. i, p. 129 (not of R. Br.) ; 



Veronica hreviracemosa, R. B. Oliver = V. salicifolia, Cheeseman, 

 Trans. N.Z. Inst., vol. xx, p. 171 (not of Vahl). 



Five species are transferred to the list of introduced plants*; — 



Cofdyline terminalis. Ageratum conyzoides, 



Geranium molle, Sonchus oleraceus ; 



Aleurites moluccana, 



and three do not occur in the islands, — ' 



Agropyrum scahrum, Coprosma Baiteri. 



Accena Sanguisorbce, 



Asplenium Shuttleworthianum is here restored to specific rank ; so that 

 the total now stands at 114 species. 



III. Geology. 



The Kernndec Islands, four in number, lie in a line extending from 

 Sunday Island, in S. lat. 29° 15', W. long. 177° 59', about S. 22° W. to French 

 Rock, in S. lat. 31° 24', W. long. 178° 51'. They are situated on a sub- 

 merged plateau, part of the submarine ridge connecting New Zealand with 

 Tonga. This plateau, which is surrounded on all sides by water more thv.n 

 2,700 m. in depth, is now probably rising, as the last movement of which 

 there is any evidence was an uj^heaval of Sunday Island to the extent of 

 about 60 m. 



Sunday Island, the largest of the group, is distant about 950 km. from 

 Tongatabu, and 1,000 km. from the North or East Capes of New Zealand. 

 Its greatest length is 10-3 km., and its area 29*25 sq. km. ; Moumoukai, 

 the highest point, is 524 m. above sea-level. 



Sunday Island is composed chiefly of pumiceous and other tuffs. There 

 are a few lava-streams, but these have little effect upon the vegetation 

 other than forming the substratum for certain of the coastal and inland 

 rock formations. The tuffs, being of a more or less 'oose nature, suffer 

 severely from the action of sea and atmosphere. The whole island is of a 

 mountainous character, and the surface has been formed by subaerial denu- 

 dation into a series of narrow spurs separating deep ravines. Towards the 

 coast these spurs usually terminate abruptly in cliffs with a sheer drop 

 to the sea of from 200 m. to 300 m. The crater occupies a large portion of 

 the island. The rim is low and narrow on the north, the lowest point being 

 only 55 m. above sea-level ; elsewhere it is high, averaging over 300 m. 

 From it there branch off three main ridges : one runs north-west from 

 Expedition Hill to Hutchison Bluff, another south-west from Mount Junc- 

 tion to Smith Bluff, and the third south-east from Moumoukai to the east 

 coast. Level ground occurs in Denham Bay, in the crater, and on Low 

 Flat and the adjoining terraces. There is a swamp in Denham Bay, and 

 three lakes in the crater. 



Except for a gravelly beach in Denham Bay, and a sandy one on the 

 north side of the island, the coast is rocky — sometimes boulder beaches ; 

 more often c\iS.'debris, consisting of large and small angular blocks of lava 



