540 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [March 10, 



much bright pyrites in them. The flora of this old land-surface 

 resembles that of the present day. 



This first trap is covered by green and brownish clay and sand, 

 which are succeeded by another trap, having a line of charred vege- 

 table matter at its base, and also having a similar covering of clay 

 and sand. These clay- and sand-deposits are regarded by the author 

 as being of lacustrine origin ; the volcanic rocks having dammed up 

 the old river-courses that formed the gully-drifts, and caused the 

 drainage water of the region to be accumulated in lakes. 



The next deposit is a coarse ochreous quartzose drift, considered 

 by the author to be the effect of some sweeping deluge ; and this is 

 also overlaid by a third bed of trap-rock, with the charred remains 

 of a forest intervening. This trap is covered by a mottled clay of 

 pure quality, also regarded as lacustrine. 



A fourth trap succeeds, covered by a superficial quartzose drift (of 

 diluvial origin, according to the author), and lying on one side of the 

 schistose hills, which are clearly denuded on the other. 



In the basin of the Yarrowee, which is covered chiefly with this 

 gravel, the author traces the run of the "gold-leads" or old gullies, 

 which have only an approximative resemblance to the ramifications of 

 the present river (see the Plan). These ancient gullies or leads 

 had a very uniform fall, which, from the smallness of the contents of 

 the gullies, must have been as rapid as 16 in 1000, while the present 

 fall of the Yarrowee is only 8 in 1000. 



Mr. Phillips urges that all the basin between the gold-leads may 

 be wrought by the aid of the water-power of the Yarrowee, — a thou- 

 sand horse-power being now allowed to run waste, which, by means 

 of reservoirs could be made available. 



The author adds that silver-nuggets have been reported on good 

 authority to have been found within thirty miles of Ballaarat. He 

 further observes that, whilst surveying the district, oscillations of 

 the spirit-bubble indicated a rocking of the earth, and that the 

 country in places sounds hollow, like a wooden bridge, horses even 

 noticing it in passing. 



3. On the Gold-diggings at Creswick Creek and Ballaarat. 

 By Mr. W. Re daw ay. (Communicated by Sir R. I. Murchison, 

 V.P.G.S.) 



[Abstract.] 



Mr. Redaway noticed first the "bluestone" or concretionary 

 basaltic lava at Creswick Creek, which composes also the rough 

 bouldered surface of the country to a great extent. In the plains 

 formed of this volcanic rock, small lakes or water-holes, from 3 to 

 12 feet in diameter, are in some places frequent. 



At Creswick Creek the different diggings perforate varying thick- 

 nesses of the bluestone, from 17 to 20 feet. Under this is 30 feet 

 of solid clay ; then darkish-coloured quartzose gravel, with abundant 

 remains of wood, to a depth of about 80 feet ; and under this the 



