Basalt. 
273 
A second fissure is noted (marked D on map), 
running in a north-westerly direction, and still retain- 
ing some decomposed basalt in situ . Further south is 
a third fissure (C on the map attached). Fig. 13 is a 
photograph of this fissure, taken from a point at sea 
level, which may be reached through the Meriveri Pass. 
The photograph shows basalt filling the lower part of 
the fissure, but now soft and decomposed. Still 
further south there are two other fissures — five in all 
— that unmistakably show they were once filled with 
basalt. These are shown as A and B on the sketch 
map. The former retains portions of the decomposed 
basalt, as an unctuous or soapy-grey and yellowish 
mass, with amygdules of decomposition products. At 
this point some very bright green colours seen in the 
decomposed rock were proved to be due to traces of 
chromium, which chemical analysis shows the rock to 
contain. 
At the date of writing, undecomposed basalt could 
be found in two places only in the vicinity of these 
dykes and fissures — the projecting knob of basalt 
already referred to, on the path down the cliff, and on 
a point of rock standing above the sea in calm 
weather, a few chains from the mainland, and marked 
G on the sketch map. The small amount of undecom- 
posed basalt remaining is noteworthy, as continued 
operations at the quarry may hide the little that there 
is completely from view. But even should the last 
traces of the basalt proper be lost, the fissures, the 
decomposed rock filling them in part, and the pris- 
