Bone Clay and Associated Basalts. 79 



Beyond both these banks the Yarrowee type is found, and 

 also on the other side of the Devonshire Creek, at its mouth. 

 The actual contact is nowhere seen, being always concealed by 

 soil, but blocks in situ on the Devonshire Creek west bank 

 above No. 3 shaft are, though decomposed, most like the Yar- 

 rowee type. At the No. 3 shaft the Durham Lead type is 

 most common, but the accessible surface excavations are in 

 the Buninyong basalt. The Yarrovvee type also occurs here, 

 probably from the shaft. 



It is easily seen that the Yarrowee flow overlies the Durham 

 Lead flow, and the disposition and amount of denudation of 

 the two makes it certain that the Buninyong overlies the 

 Yarrowee flow, independently of the somewhat doubtful super- 

 position in the Devonshire Creek, The lava flows from 

 Buninyong would, therefore, be the newest, and from the 

 amount of erosion which they have undergone, need not be 

 of any great age. 



The height of the basaltic plain above the creek varies, but 

 only at two places does it exceed that close to the No. 1 

 shaft, viz., about 30ft. These are at a short distance before 

 its junction with the Yarrowee Creek and at a point at the 

 south boundary of the township, where the Devonshire Creek, 

 coming from the ranges to the east, first meets it, and is 

 deflected southward. There is nothing to indicate that any 

 appreciable portion of the basalt has been I'emoved by denu- 

 dation — indeed, near the No. 1 shaft and near the mouth of 

 the creek this could not have been so. At the Devonshire 

 shaft east of the creek, near the No. 8 shaft, 40ft. of basalt 

 was passed through, under 70ft. of drift and clay. If this is 

 from Buninyong, it is not the present surface basalt. 



The area in which the bones occur would almost necessarily 

 be a lake or swamp, with the present relative levels, as the 

 bottom of the basalt is about 1195ft. above sea level, and this 

 is very little above the present level of the Yarrowee Creek, 

 whose course can only have been very slightly affected by the 

 Buninyong basalt, and must have been higher than at present. 



On the other hand a very considerable time probably elapsed 

 between Yarrowee and Buninyong flows, and also very likely 

 between the Durham Lead and Yarrowee flows. 



