i a ai a aa lS a ca 
ANNIVERSARY ADDRESS. 67 
Bathurst, and Mudgee. That this sea may have been of consider- 
able depth, is perhaps implied by the development of radiolarian 
cherts near the Jenolan Caves. Folding and elevation ensued, 
and in Upper Devonian time there was heavy sedimentation pro- 
longed into Carboniferous time. While the conditions were still 
mostly marine the frequent occurrence of interstratified beds of 
conglomerate shews that land was not far distant to the west of 
the present position of the Blue Mountains. The greater portion, 
however, of the present New England tableland may have been 
covered by a very deep ocean, as would appear from the very 
extensive development of radiolarian red jaspers in that district. 
Then followed the powerful folding of the Carboniferous (Gympie) 
and Upper Devonian formations, a great land-building epoch in 
the history of the Australian continent. When this folding had 
nearly ceased, and a great range had now become established 
west of the present site of the Blue Mountains, sediments derived 
from the former began to be deposited in the shallow seas extend- 
ing from near Penrith to the continental shelf. These constituted 
the strata of the Lower Marine Series (Permo-Carboniferous). 
Swampy or lacustrine conditions succeeded, and the Greta coal- 
measures were laid down over an area about two hundred miles 
long from north to south, by from thirty to forty miles from east 
to west. A considerable subsidence ensued during which the 
waters of the Pacific penetrated to at least as far inland as Mount 
Lambie, about seventy-two miles inland from the present coast. 
The subsidence amounted to a maximum of about 5,000 feet in 
the Maitland district, 2,500 feet in the Illawarra district. The 
strata of this epoch belong to the Upper Marine Series. The 
cessation of the subsidence was accompanied by volcanic eruptions 
most extensively developed in the Kiama neighbourhood, but 
represented also on a smaller scale by the voleanic rocks near 
Rylstone. Swampy conditions returned on a larger scale than 
ever, and the Bulli-Newcastle coal-measures were formed in the 
Blue Mountain area; while in the Newcastle area a middle group 
of coal-measures (The Tomago Series) was developed as well, being 
