The South Australian Naturalist. 
109 
With the able assistance of Mr. H. C. Hosking, B.A., Dr. 
Fenner investigated the limits of the ash deposits and mapped 
these as shown in fig. 2. The unsymmetrical distribution of the 
finer material at once suggests the influence of the prevailing 
winds as the chief agent of its distribution. Detailed enquiries 
serve to confirm the idea that the ash distribution was governed 
by winds similar in direction and velocity to those of the pre- 
sent day. 
Summing up the large amount of evidence available, it is 
concluded that Mount Gambler and its associated vents repre- 
sent a western marginal outburst from the great basaltic 
magma that gave rise to the Victorian Newer Basalts, occurring 
near the close of the Newer Basaltic Period and possibly dating 
to quite late prehistoric time, possibly just prior to the appear- 
ance of the blaekfellow on the scene. 
That there were at least three craters at Mount Gambier 
itself is clear from the available evidence. There was a brief 
explosive phase prior to the basalt flow, and the former prob- 
ably came from the v^estern crater, as did the lava. Possibly 
