16 W. H. WARREN. 
which had intersected the coal measures. At the Pyrmont Quarry 
it was ascertained that between the bed of sandstone known to the 
quarrymen as the “bottom block” and the top of a bed of shale 
immediately underlying it, there occurred a well-marked layer of 
barytes, exhibiting on its surfaces a number of large well-formed 
crystals; the layer was about half-an-inch in thickness. Mr. Smith, 
the Mineralogist to the Technological Museum, had a short time 
previous recorded a somewhat similar occurrence of barytes in 
Hawkesbury Sandstone, near Cook’s River. 
During the Geological Examination of the Kiama District, a 
sketch map and sections were prepared showing the relation of the 
highly interesting series of volcanic rocks of that neighbourhood to 
the Bulli coal-measures, and also to the associated marine strata. 
The details of this examination, when elaborated, are intended to 
form the subject of a paper for the Society during this year. A 
brief summary, however, of the conclusions already deduced may 
be given here. Towards the close of that portion of the Permo- 
Carboniferous period, when a shallow ocean extended from Ulla- 
dulla on the south, to Port Stephens on the north, and inland as 
far as Mittagong, Rydal, and Somerton, near Gunnedah, volcanic 
eruptions of a violent paroxysmal character broke out in the 
neighbourhood of Kiama. The approach of the lavas, which flowed 
from the centres of these eruptions, is heralded by the presence in 
the uppermost of the marine Permo-Carboniferous mudstones of 
large lumps of lava and isolated crystals of black augite, bedded 
side by side with marine shells. 
Solid sheets of basic lava succeed, the highly brecciated character 
of which considered in conjunction with the presence of numerous 
and very large amygdaloids, implies that the lava flowed into the 
ocean, where the steam, generated by the contact of the molten 
rock with the sea water, occasioned a series of violent explosions, 
which completely shattered in places the already partially cooled 
crust in the ipper portion of the lava flow. South of Kiama there 
is evidence that there were three lava flows of this kind, probably 
almost synchronous, each newer flow over-riding its predecessor, 
