67 



and extending to tKe quartzite band passing between Sections 

 111 and 726, on the east, the soils and subsoils — with a few 

 exceptions, where outliers of the Miocene beds occur — have 

 been derived from the decay of the underlying fundamental 

 rocks. Where the substratum is clay-slate, and the soil and 

 subsoil of moderate depth to the bed rock, these, though at first 

 less fertile than those derived from the Miocenes, are much more 

 enduring. 



Water, Surface and Stjbterraxean. 



Surface. — Surface water at Crawler during the summer 

 months is obtained chiefly from the IS'orth Para. Though a 

 plentiful supply pours down the channel of the South Para in 

 winter, the stream, on reaching the drift formation, ceases to 

 flow during the months of summer. In Cockatoo Creek a 

 moderate supply is sustained at all seasons of the year ; and 

 Mr. John Martin informs me that Spring Gully, though at nO' 

 season of the year a large stream, continues to trickle through 

 the pebbles in its bed during the dry months of summer. In 

 connection with these creeks, I might here remark that the- 

 drainage area of both is, in a great measure, overlain with 

 Miocene beds. As to the hydrological properties of the Up- 

 land Miocene, I refer to Transactions of the Eoyal Society 

 of South Australia, vol. iii., page 110. None of the minor 

 gullies throughout the tract embraced in sketch sustains surface 

 water all the year round. 



Waier-hearing Froperties of the Drift at Gaivler compared 

 ivitJi those of Munno Para, East of Smith field. — The Grovernment 

 well at Gawler, is undoubtedly situated in the drift area, 

 and according to Parliamentary paper, 5th July, 1881, a section 

 of the strata penetrated is as follows : — 



Surface portion of the shaft, chiefly gravel and sand, with 

 some bands of clay intervening. "Water struck 

 Thirty-five feet from the surface, sand and boulders 85 feet. 

 vShaft sunk a further depth of 17 feet ... ... 17 " 



Tubes were driven down a further depth of 40 feet 



into sand and gravel ... ... ... ... 40 " 



Total depth of perforation 92 " 



The base of these interbedded clays, sands, and gravels 

 which I refer to the Drift, is only 75 feet above the present 

 sea level. That they are water-bearing here, and not 

 elsewhere in Munno Para (see Transactions of the Philoso- 

 phical Society of South Australia for 187S-9, page 68), 

 can only be attributed to the excess of inflow over the outflow. 

 That this excessive inflow is not due to subterranean permea- 

 tion direct from the older rocks is pretty evident, because no 



