RECENT SUBMERGENCE OF COAST AT NARRABERN. 231 
by the wind, the waves, and the currents along the coast 
line near Narrabeen. In places the old estuaries, as at 
Narrabeen and Deewhy, have been converted into lagoons 
through the pushing out of sand spits chiefly from their 
southern ends and directed northwards. In other cases as 
at the Curl Curl Lagoon, about two miles northerly from 
Manly, the reclamation is so mature that all the old lagoon 
is now obliterated through silting, with the exception of 
the comparatively small area occupied by the modern 
Curl Curl Lagoon. 
A glance at the geological map of Sydney and its neigh- 
bourhood, including the County of Cumberland, recently 
issued by the Geological Survey of New South Wales, shows 
that the rocky hill of sandstone between the Freshwater 
and Cur! Curl Lagoons, in recent times formed an island 
previous to the complete silting up of the old estuary which 
separated it from the main land. The same remark applies 
to the Quarantine Ground near Manly,as well as to that long 
strip of sandstone cliff and hill which stretches from South 
Head to Ben Buckler near Bondi; obviously this area has 
in recent times been an island before the Strait, now 
occupied by the silt beds of Rose Bay and the sand hills of 
Bondi, separated it from the mainland of Bellevue Hill and 
Bondi. Still further north in the neighbourhood of Lake 
Macquarie and the delta of the Hunter the general con- 
figuration of the country supplies conclusive evidence of 
recent submergence. Lake Macquarie itself is obviously 
an old drowned valley, and so isthe Hunter estuary between 
Newcastle and Port Stephens. 
III. Evidence supplied by bores, shafts, etc.—In addition 
to the case of Shea’s Creek already quoted, probable 
evidence of recent submergence of the coast line was 
afforded by the trial shaft for the North Shore Bridge made 
between Dawes’ Point and MacMahon’s Point. Atadepth 
