70 Proceedings^ of the Royal Society of Victoria. 



glomerates form a more or less flat country, which extends to 

 the Djerriwarrah Creek. Here the beds are found resting 

 directly on the Silurian rocks. 



With the exception of the basalt, the remaining post-glacial 

 beds do not call for extended notice. Along the Goodmans 

 Creek they are represented by a great development of boulder 

 drift, often very heavy, and gravel. A ferruginous conglomerate 

 is met with at difierent levels ; the highest beds of this, which 

 rest directly on the glacial rocks, are possibly continuous with 

 those east of the Pyrete Creek. In the absence of fossil 

 evidence, and having regard to the great variation of lithological 

 character which marks the tertiary beds of this district, no 

 attempt can be made to collate these beds with those lying 

 further west. 



On the south-east extremity of the basalt there is a thin 

 capping of sand and water worn gravel, similar in composition 

 and having the same level as the gravels found S. and S.E. of 

 Bacchus Marsh, and well exposed in the Railway cutting S.E. of 

 jbhat town. 



Basalt. — The point of eruption of the busalt flow was Mount 

 Bullengarook, some seven miles to the north of the township of 

 Coimaidai. The basalt is almost entirely confined to the area 

 between the Goodman's and Pyrete Creeks, only one outcrop, 

 and that a very small one, having been noticed by us west of 

 the. former creek, and no outcrop east of the latter creek. The 

 basalt enters our district at an elevation of about 1100 feet abo^e 

 Coimaidai, and its thickness here is approximately 250 feet. At 

 this spot it is about 300 feet wide, with a small slope to the 

 south. This breadth is maintained faii'ly constant for a con- 

 siderable distance south, but at a point on the Bullengarook 

 Road, some 460 feet above Coimaidai, it rapidly narrows. At 

 this place it is only forty feet wide and a few feet thick. 

 Directly after leaving this spot, locally known as "The Neck," 

 the basalt widens out into a broad plain, which, with a slight 

 southerly slope, extends to the boundary of our area, where it 

 has a thickness of between thirty and forty feet. 



From its position and character we think that the basalt 

 found west of the Goodman's Creek came from Mount Bullen- 

 garook. If this is so the creek must have eaten its way through 



