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miles to the southward of Ardrossan. The difference in 

 altitude of the respective river deposits is about 200 feet, 

 and may mark the deepening of the river courses, consequent 

 on the gradual rise of the land, in which case the deposits 

 at sea level would be relatively younger than those on the 

 higher terrace. There is every reason to think that, at that 

 time, the rift valley was already well developed, and that 

 a wide and shallow valley existed in -the region of the present 

 Gulf St. Vincent, which would form the main longitudinal 

 waterway from the interior, and into which the lateral 

 streams would find their way. 



Few features have survived in the inland districts to 

 throw further light on this subject. Yorke Valley, which 

 probably represents one of these ancient lines of drainage, is 

 a peculiar elongated basin-shaped valley that maintains a 

 north and south direction for many miles. The main south 

 road from Maitland to Yorketown passes along the bottom 

 of this valley. No creek occupies the valley, but there is a 

 soakage that finds its way southwards, where the valley ends 

 in a saline marsh. In the neighbourhood of Maitland the 

 valley has been excavated in the Pre-Cambrian basement 

 rocks, which on the rises on either side are sometimes capped 

 by thin layers of Cambrian grits or limestones. Every feature 

 of this valley suggests river erosion, but belonging to a past 

 age. It has no outlet, and is gradually filling up by rain 

 wash from the sides. Unfortunately there are few wells 

 in the district from which can be gathered any information 

 as to the nature of the alluviation in the valley. Mr. B. 

 Cornish called my attention to a bore that had been put 

 down near Yorke Valley Public School, on Mr. Smith's 

 land ; but the only information concerning it that could be 

 obtained was that the bore was 413 feet in depth, the first 

 30 feet was in clay, and there "followed rocks of various 

 kinds." Granite was met with in the bore, but it is not 

 likely that so great a depth would have been sunk in this 

 rock. 



Little need be said on the recent river drainage of Yorke 

 Peninsula, as no connected water system exists at present. 

 The area is limited in extent, and is almost flat, so that the 

 run off is practically nil. There are no inland waterways, 

 and there are only a few small channels near the coast which 

 carry water, and these only for a few hours after a heavy 

 rain. In this respect Yorke Peninsula bears a close likeness 

 to Eyre Peninsula, where there is practically no natural 

 delivery of the drainage to the sea. In southern Yorke Penin- 

 sula, where rock solution has led to the formation of 

 depressed basins, the conditions are similar to those of inland 



