sunk by the Govermneut has revealed a great thickness of 

 Tertiary beds resting directly on a primary rock composed of 

 blue slate containing iron pyrites and bands of quartz. The 

 Tertiary beds have been critically discussed by Professor Tate 

 in Vol. ly. of the Society's Transactions, &c., and by him the 

 series are divided into two portions, the upper beds being 

 classed as "Recent Marine" and the lower beds "Pliocene 

 Drift." 



The Recent Marine does not extend far inland, and is suc- 

 ceeded on the surface by red loam, underlaid by red clay, 

 which continues to Balaklava. ^Sinkings at this place pierce 

 the loam and clay at about 80 feet, and then enter water- 

 iDearing strata of sand and gravel. The same occurs at Hal- 

 bury on the Blyth railway line, and at several points in the 

 scrub south of Balaklava. East of this township the red loam 

 is found surmounted by a crust of travertine, and this in turn 

 is covered by 20 to 30 feet of blown sand of a light-brown 

 colour. It is this sand which by forming mounds gives the 

 undulating character to the plains. A fine section of the sand, 

 travertine, and loam is exposed by a railway cutting on the 

 Blyth line just over the bridge crossing the Wakefield. These 

 sandhills continue right back to the ranges, and where they 

 adjoin the older rocks often develop flat beds of a fine-grained 

 brownish-black ferruginous sandstone, which is extensively 

 nsed for road metal. The manner of its occurrence is like 

 that of travertine, and doubtless owes its origin to similar 

 causes — aqueous solutions concentrated by evaporation. 



Along the line of section no exploration has been made 

 deeper than the gravel which underlies the red clay, but at 

 several points southward the search for water has resulted in 

 greater depths being reached. The Hundreds of Dalkey and 

 Grrace are by this means pretty well knovru, but in no instance 

 have the wells reached the primary rocks. Among the sand- 

 hills west of Owen railway station wells which have been sunk 

 •over a tract of country six miles wide have passed through the 

 gravel and entered blue clay at a general depth of a little over 

 100 feet from the surface. Twelve miles farther south in a 

 well at Mallala — 115 feet above sea level — the blue clay was 

 met with at a depth of 80 feet. The water supply at this depth 

 being insufficient and of poor quality, a borehole was continued 

 from the bottom. The blue clay continued to a depth of 150 

 feet further, and then the drill entered a bed of quicksand and 

 gravel, which afforded water with such pressure that it not only 

 rose to the top of the bore, but flooded the well to a depth of 

 40 feet, at which point the water has found its level, or, what 

 is more probable, the lateral soakage is equal to the supply 

 from below. This well was sunk by the Milling Company for 



