104 Lieut. Baddeley on the geognosy 
same porous exterior as before-mentioned, nor was this charae- 
ter of porosity confined to the surface, as a specimen brought 
from the place exhibits it both internally and externally in so 
perfect a manner as to afford an excellent sample of a mille 
stone ; its quantity cannot be stated, but the writer believes it 
to be abundant. It should be generally known that good mill- 
stones are often found among syenitic rocks. 
Several rocks in front of the bottom of this bay, which by 
the rising of the tide are converted into islets, were examined. 
The first met with was syenitic gneiss, having a bearing nearly 
north and south, and dipping to the west at a high but va- 
riable angle. It sometimes loses its character of gneiss and 
maintains those only of syenite ; the usual imbedded masses 
of trap are present under all the appearances before described, 
and one additional : some of the snake-shaped imbedded 
pieces were broken through the middie apparently, and the 
fragments separated from each other, like the well-known shifts 
in veins, but no corresponding fracture in the rock was seen. 
(pl. 6, fig. 3,) 
Almost all the rocks examined inthis place were of the same 
description, differing only in their dip which was sometimes re- 
versed. It was here, however, that we observed for the first 
time regular and conformable strata of the same aggregate as 
that found imbedded 1m the syenite, and to which, from its inter- 
fering character in other places, we are unable to affix any other 
name than the general one of trap, using this term here as else- 
where, without the implication of any theory to designate cer- 
tain aggregates in which hornblende predominates. Water- 
worn fragments of compact shell limestone were here seen, thie 
color of which was grey and fracture flatly conchoidal and sharp- 
edged. 
Leaving these rocks, others to the south-eastward in the same. 
bay were visited ; they borea great general resemblance to the 
first 
