1855.] C. FORBES — NEW ZEALAND. 521 



2. On the Geology o/" Georgia, United States. 

 By W. Bray, Esq. 



[Communicated by the President.] 



(Abstract.) 



In this communication the author gave a sketch of the distribution 

 of the alluvial, tertiary, cretaceous, palaeozoic, and crystalline for- 

 mations of the State of Georgia, through which he had lately 

 travelled. 



3. On the Geology of New Zealand ; with Notes on its Carbo- 

 niferous Deposits. By Charles Forbes, Esq., Assistant 

 Surgeon, H.M.S. Acheron. 



[Communicated by Sir H. De la Beche, F.G.S.] 



(Abridged.) 



Coast-line of South and Middle Islands. — In a country in most 

 places so difficult of access, and so thickly wooded, as New Zealand, 

 little more can be done than simply to specify the names, and as 

 nearly as possible the relative positions, of the various rocks which 

 present themselves along the sea-coast ; for, with the exception of an 

 occasional landslip, there are no other means of arriving at a know- 

 ledge of the geological formation of the country. The water-courses 

 are either precipitous torrents, or gentle streams flowing through 

 alluvial deposits ; in no case showing a regular and well-defined series 

 of sedimentary rocks. The nearest approach to such a section was 

 found at the foot of Mount Grey in Port Cooper Plains ; it will be 

 alluded to hereafter. 



The rocks which appear to be the fundamental rocks of the 

 Middle Island, are — granite, gneiss, mica-slate, clayslate, and other 

 metamorphic schists, with rocks of igneous origin, including basalt, 

 amygdaloid, porphyritic lavas, volcanic tuffs, obsidian, serpentine, 

 and greenstone (jade). Associated with these on the sea-coast are 

 carboniferous deposits, made up of limestones (generally fossilife- 

 rous), sandstones, grits, shales, and seams of lignitic and imper- 

 fectly formed coal, covered in most places by a remarkable deposit 

 of gravel, composed of water-worn pebbles, which are chiefly, and in 

 some places entirely, of white quartz. This deposit in many places 

 is several hundred feet in thickness. It is found in Massacre and 

 Blind Bays, at the Wairoa Plain, and again covering the plains from 

 Port Cooper district to below Otago. The quartz-pebbles not only 

 cover the coal-beds at Massacre Bay, but are imbedded in the coal ; 

 as is also the case in the lignite of Otago, which is directly overlaid 

 by this pebble-deposit. 



The centre of the Island is occupied by a chain of mountains com- 

 posed of crystalline and metamorphic rocks. As far as is known, the 

 former show themselves only in the extreme south and south-west. 

 Stewart's Island and Roubouki are composed almost entirely of a 

 dense blue-coloured granitic rock, containing hornblende in the place 



