Liinhwrglte Rock. 125 



down on the south-eastern side to lower ground bounded by a 

 small creek. The mound has been rendered more conspicuous 

 by the accumulation of excavated rubble which has been 

 thrown out around the area worked for the stone. No actual 

 junction with the country rock (silurian mudstone) was found, 

 even after prolonged search ; but close at hand, near the small 

 creek before mentioned, the mudstone is indurated in a peculiar 

 manner, and a small monad nock stands out as the result of 

 unequal hardness and encircling denudation. 



QEOLOQICAL SECTION FRor^BURKE ROAD to DONCASTER TOWER 

 Lenc,tm of SccTiOM l+.Miuas. V£RTic/M_ sc^ue E.xi\CiqELRA.-rE.D i3.lT-.~ie:s. 



The height of the outcrop of the lava above sea-level is 270 

 feet. The exposure, which is situated on the sloping sides of the 

 Koonung-koonung Creek basin, appears to have been discovered 

 many years ago, and was locally used for supplying a hard 

 stone, of Avhich, by the way, there is a decided lack in this 

 locality. Some of the lava was formerly employed for metalling 

 the Doncaster Road, but was eventually given up on account 

 of the objection of the stonebreakers to use material harder than 

 the CollingAvood bluestone, to which, together with the local 

 indurated sandstone, they have noAv adverted. The conspicuous 

 part of the mound formed by the lava and the excavated rubble 

 is about 230 feet in length and about 100 feet broad. Altogether 

 with the exposure of lava and volcanic soil on the south-eastern 

 slope, this area would be increased more than four times. 



The mode of occurrence of the rock at once conveys the idea 

 that it is a volcanic plug or neck, w^hich has broken into and 

 through the silurian mudstone and sandstone of this district. 

 That it is a pipe or terminal flow is fairly evident from the shape 



