ROCKS FROM NEW BRITAIN AND NEW IRELAND, 49 
wa, from river bank. A dusky purple slate-coloured igneous 
on full of small amygdaloidal cavities. The cavities are for the 
most part about }” across, but some are ——s, 1 inch long, but the 
width and depth not more than about 4th to }”. 
These cavities are arranged in nai regular me ~~ are 
drawn out in the direction of the flow of the once fluid 
Many of the cavities are filled with quartz; the oy parts 
rans 
ed upon a lining of chalcedony. Some contain a thin 
tals, se 
velvety coating of dag chlorite, and others are completely 
filled with chalcedon 
Chemical composition. 
Loss at 100° C. 402 
Silica 67664 
Alumina 15402 
Iron sesquioxide 1 
APO TAGRORIOS exciseivcasy caries trys 3°491 
ONO MONGKIGG 5 0ss'c4<; +e cowors un’ “762 
Lime 2-963 
Magne trace 
Carbon dioxide oS 
Potash 1 ‘220 
Soda 6010 
Tough, b reaks with a fairly even fracture ; the Ra ee planes 
of elongated twin i oe of felspar, embedded i in a granular paste, 
are well shown in place 
Specific gravity, in ashe at 17° OC. 2694. 
Amongst the New Ireland specimens is a rock with bright 
Steen mottlings, looking almost like a serpentine, but it is not 
Serpentine, probably a decomposing igneous rock. 
Specimens From New BritTalnN. 
ma —Most of the as ea spouse specimen 1S _ 
ofa cae Sethi colour ; cine is rather more vesicular than the 
eae eae: this on analysis yielded the foll following results: 
Mo. Bot. ©777en, 
1897. 
