AUSTRALIAN QUATERNARY CLIMATES AND MIGRATION 57 



Miss J. Hope Macpherson, coneliologist to the National Museum, 

 has identified the land shells found in it as Amena acutispira 

 Tyron and Lijmnaea brozicri Smith, forms found in slow moving 

 water or a marsh. 



The hole was put down in an accumulation (Fig. 9, YDZ) of 

 stratified tuff and. tuffaceous limestone on a river-terrace, C (Fig. 

 9) that was formerly covered by 5 feet of stratified tuff, now 

 removed by slip-erosion. The axe was found at a depth of 3 feet 

 9 inches, but its original depth, when the uppermost stratified 

 layers, D (Fig. 9) covered it, was about 9 feet. 



It was not possible to obtain a single section giving all the 

 features in evidence. Fig. 9 is a composite section. 



X_ MERRI RIVER 30ft D 35ft. >^ 



^\ 20ft C /-"-'- ^-^ 



Purnlirr\ B . ^ILE WITH AXE ,^-^Meerai. 



FIG. 9. 



Composite section across Merri River in the direction of a fence-line on the left 



bank bearing N. 53° E. 



The succession of events may be summarized as follows : 

 The valley XYZ was cut in Tertiary limestone, probably during 

 the last glacial period, and was periodically covered during the 

 Postglacial by tuff from Tower Hill, 7 miles to the west, until the 

 tuff reached the level XDZ. While the valley XYZ was being 

 infilled, the Merri River continued to flow, although it was from 

 time to time impeded by the accumulating ash when lacustrine or 

 marsh conditions prevailed. It ultimately cut the channel XYD 

 along the eastern contact of the tuff with the Tertiary limestone 

 to a depth of 40 feet below the surface layer XDZ. In this channel, 

 the flood-plain A, about 150 feet wide, formed and has since been 

 entrenched to a depth of from 15 to 16 feet by the vertical erosion 

 following the last lowering of sea-level. The surface of the flood- 

 plain was at the time of inspection 11 feet above the level of the 

 water in the Merri River, which was 4 or 5 feet deep ; the bed of 

 the River opposite the hole in which the axe was found is about 

 30 feet above the level of low water at Warrnambool Bay. The 

 time taken for the accumulation of the 9 feet of tuff covering 

 the axe together with that taken for the valley XYD to reach 

 maturity is the age of the axe. The flood-plain A was formed at 

 or about the Postglacial Optimum, probably just before the rising 

 sea-level of the Postglacial reached its maximum, and after Tower 

 Hill had ceased to be active: the vertical erosion of the Merri 



