
TINDALE—SUBDIVISION OF PLEISTOCENE 629 
eliminated and the latest dunes may pile up ou the original shoreline, as perhaps 
is happening in the vicinity of the mouth of the Glenelg River. At this stage 
the eoast has been brought to grade, and the foreshore will be a relatively deep one. 
Factors intiuencing the rate of development of the various sections of the 
coast of the South Kast inelude the following: 
(a) Initial slope of the land and of the continental shelf, 
(b) The induration of the sediments subjected to marine erosion, 
(ec) Aspect of the coast and its orientation to directions from which major 
currents and slorm waves arrive. 
(d) Set of coast-wise currents and drying winds determining the resting 
places of those parts of the products of erosion which are not transported away to 
deep water. 
(e) Rivers, estuaries and their deposits, 
All these factors are of importance. As has already been explained, the 
width of the continental shelf to 100 fathoms varies within wide limits: about 
15 miles off Carpenter Rocks, 20 miles off Glenelg River, 25 miles off Rivoli Bay 
and between 80 and 100 miles off the mid-point of the Coorong, 
In general, the stave of maturity reached by the present shoreline of the 
South East depends on the slope of the continental shelf. Where, as near the 
Glenelg River, off Blackfellow Caves and at Beachport, it is relatively steep, the 
shores are in stages of early maturity. Fronting the shallower coastal waters of 
the Coorong the fore dunes have yet scarcely more than begun to eneroael upon 
the lagoons and shore development is in a move immature stage. 
The types of land surface subjected to wave attack in the Sonth Bast inelude 
granitic domes, dolomite beds, hard limestones, soft shelly limestones, silts, sands 
and flint boulder beds. The flint boulders, derived by erosion from Miocene 
sediments, form veritable breakwaters on some shores, and may affect materially 
the rate of erosion. At some places small outcrops of granite have withstood the 
greatest efforts at levelling made by the sea, although usually on strand plains, 
present and Pleistocene, they are all but planed off level with the strand itself. 
Good examples ocenr at Brown Cattle Creek and Papajara, both in the Hundred 
of Duffield, and at Lantjin Swamp, Wundred of Landseer. 
At the northern end of Lake Bonney there is a typical transverse bar 
eomposed of lakeshell detritus, which has eut off a sexment of a former larver lake, 
extending to the north, Immediately to the rear of this beach isa slightly older 
one with marine and estuarine shells showing that at some recent period 
Lake Bonney had greater access to the sea than at present. 
Eyidenee at Beachport, where breaching of the Recent dunes by the sea has 
