28 Excursion to Mont Albert and Balwyn. [^'"'u,,^'''^' 



EXCURSION TO MONT ALBERT AND BALWYN. 



The assemblage at Mont Albert station on Saturr^ay afternoon, 

 8th April, consisted of 17 members and visitors, and we 

 were favoured by an especially line afternoon and a clear 

 atmosphere — the latter a desirable condition where scenery 

 is the objective. For a demonstration in physiography and 

 general geology, the facilities afforded in this district from 

 the various view-points can scarcely be surpassed. From 

 the Reservoir Hill (420 feet) a magnificent panorama is 

 displayed, and it was here that the first halt was made. To 

 the south-east and south the lower slopes of the great Yarra 

 or Nillumbik pene-plain were seen, merging into the coastal 

 plain beyond Oakleigh to Brighton and Cheltenham. To the 

 east, the almost level country of the same pene-plain was 

 noticed, looking as if sharply cut oft by the Brushy Creek scarp 

 and backed by the prominent Dandenong Ranges, whilst a few 

 points to the north the rising ground of the Mitcham axis could 

 be discerned, forming a parallel tract north of the railway line 

 nearly to Croydon. The monadnocks (residual hillocks) of 

 Pine-Mont, north-west of Ringwood, and Croydon Hill, 

 beyond Ringwood to the east, are prominent features in the 

 middle distance. These features were the more easily under- 

 stood in the light of the recent work of one of our members, Mr. 

 J. T. Jutson, described in papers read before the Royal Society. 

 A short sketch of the volcanic history of this part of Victoria 

 was included in the demonstration at this part of the pro- 

 ceedings. At this elevation of 420 feet the highest part of 

 the pene-plain is reached, with the exception of Mitcham, at 

 about 500 feet. The Reservoir Hill is covered with the Tertiary 

 sand-cap of Kalimnan age, and represents a remnant of the 

 once widely spread cover of the pene-plain extended to our 

 view. In places the Tertiary sand has formed small, hard con- 

 cretions, probably through partial solution of the sand grains 

 by alkaline water and acids derived from decaying organisms 

 at the surface, the cementing substances being both limonitic 

 and siliceous. The arenaceous character of the soil on this hill is 

 readily remarked from the abundance of English Broom, Cytisus 

 scoparius, and the sand-loving tea-tree. Lcptospcrwurn scoparium. 

 Turning down Elgar-road to the north, we passed into the reserve 

 of the Surrey Dive. Originally a brick-pit, this splendid diving 

 reserve has been filled with water, and is now apparently 

 supplied from springs arising between the Tertiary sand-cap 

 and the bed-rock (Silurian), the junction of which we noticed 

 near the gate of the reserve. The springs are partly under- 

 ground, and run through a series of " crab-holes," and the 

 open runnels are marked by a growth of rushes. One face of 

 the Dive shows a surface parallel to a leg of an anticline, whilst 



