172 



On the Discovery of Marine Deposits of 

 Pliocene Age in Australia. 



By Professor Ralph Tate, F.G.S., F.L.S., &c. 

 [Read August 5, 1890.] 



Towards the end of last year a deep bore in search of water 

 was successfully completed at the Australian Smelting Company's 

 Works at Dry Creek, Adelaide. A summary of the beds passed 

 through, which here follows, has been furnished me by Mr. John 

 Provis, the Company's General Manager : — 



" The bore was commenced with an auger big enough to take 

 an eight-inch tube, and was sunk 120 feet through clay ; after 

 100 feet had been reached, occasionally thni seams of sand occurred 

 which carried a little water. At 120 feet the tube reached the 

 sand, and a good supply of water was struck, estimated at about 

 30,000 gallons per day. The sand rose so rapidly, however, that 

 it was impossible to keep it out, and the tube was constantly 

 choked. Owing to the bore being suspended as soon as water 

 was struck, the sand and clay packed so tightly round the tube 

 that it was impossible to drive it, and another tube had to be in- 

 serted ; this was put down a considerable distance further, in a 

 very jfine sand, but eventually shared the same fate. As a last 

 resource, a third tube was inserted, and arrangements were made 

 to carry on the work night and day without intermission. 



" A little water began to flow below 300 feet. At about 320 

 feet we came on to the marine shells, and these continued down 

 to about 400 feet. At 400 feet to 410 feet very few shells oc- 

 curred, and a little clay was mixed with the sand. There were 

 also occasional pebbles of quartzite and schist. At 400 feet water 

 commenced to flow very freely, and at 410 feet the flow increased 

 to a quantity estimated at 100,000 gallons per day, and continues 

 to-day (July 5, 1890) as strong as when first struck. There is 

 also a marked improvement of the quality of water* now 

 flowing." 



The site of the bore is about 14 feet above sea-level, and is at 

 the margin of the Recent Marine silts overlapping the red loams 

 of the Adelaide Plain. The upper 120 feet of the bore-section 

 doubtlessly belong to the Pliocene or Mammaliferous Drift, but 

 until the fossiliferous bed at 320 feet was reached I had not 



* See Appendix. 



