212 



The large amount of the latter class of rock in the neigh- 

 bourhood suggests that the Cambrian limestones probably 

 form the bed rock of the district. 



(b) Raised Beaches. 



A common building stone in use at Port Victoria and 

 neighbourhood is a shelly limestone, obtained from a raised 

 beach area situated 2| miles to the southward of the town- 

 ship. I was informed that this deposit is on the landward 

 side of the sandhills, covering low ground, several square 

 miles in extent, and in wet seasons forms a swamp. The beach 

 being raised above sea level and receiving surface waters highly 

 charged with calcium carbonate, the lime conveyed in this 

 way has cemented the shelly deposits forming a recent 

 fossiliferous travertine. The stone is tough, and can be got 

 in good-sized blocks, and is used for road metal as well as for 

 building stones throughout the district. In the stones that 

 came under observation, Bulla australis was present as a 

 common form. 



There is a raised beach in the neighbourhood of Parara,. 

 but its location could not be definitely fixed. Examples of 

 Area trapezia, a very characteristic shell in the older of the 

 raised beaches of South Australia and no longer living in 

 South Australian waters, occur in considerable numbers on 

 the beach, and one example embedded in sandstone was picked 

 up on the beach near Parara. It is probable that in this case 

 the "raised" beach is situated below high-water level, as 

 occurs also with the same bed in the vicinity of Port 

 Adelaide. 



(c) Subsidences. 



Some of the coast features on Yorke Peninsula indicate a 

 certain measure of subsidence, a movement which is probably 

 in process at the present time. The evidences may be sum- 

 marized under the following phenomena: — (1) Submerged 

 platforms of travertine limestone at Parara, on the shores of 

 Gulf St. Vincent, and also at Balgowan, on Spencer Gulf. 



(2) Submerged "raised" sea bed, with subfossil shells, 

 imbedded in an indurated sandy matrix, south of Ardrossan. 



(3) Juvenile coast lines, indicated by narrow beach and 

 several feet of water at base of cliffs at high tide, seen at 

 Ardrossan, "Sliding Pocks," Edithburgh, and elsewhere. At 

 "Sliding Pocks" the Cambrian limestones dip directly into 

 the sea without being breached by the water (see pi. xxi.). 



The fact that the coast line of South Australia, as a 

 whole, gives evidence of recent uplift is quite consistent with 

 the view of a recent subsidence. At Port Adelaide there are 



