69 
latitude of Hallett’s Cove, which agrees with North Africa and 
the southern shores of the Mediterranean in the opposite hemis- 
phere, we might have fallen back on the iceberg theory if the 
features had been reconcilable with such an hypothesis. This, 
however, is inadmissable. berg ice could not possibly polish and 
groove hard rocks over extensive areas, whilst maintaining definite 
lines of erosion and striz, such as occur at Hallett’s Cove. The 
polished floor near the coast is indeed a huge roche moutonnée in 
the form of a ridge, with an elevation of about 20 ft., presenting 
uniform lines of glaciation on all sides. I am led to think that 
only terrestrial ice of great thickness and operating through a 
long period could produce effects such as have been referred to. 
Again, as far as can be judged at present, the morainic matter 
has been gathered from local, or at least South Australian, 
sources. Moreover, most of the beds are distinctly stratified 
(which could scarcely be expected of iceberg debris), and in their 
deposition show thin, alternating beds of different lithological 
character indicating the presence of water operating under quiet 
conditions. Lastly, in the absence of organic remains the proof 
is wanting that the Hallett’s Cove beds are of marine origin, for 
whilst many of the clay bands are eminently adapted for the 
preservation of such, no fossils have hitherto been discovered in 
them. The land plants of the Bacchus Marsh beds seem to 
point to fresh-water conditions in analogous formations in the 
adjoining colony, and I should anticipate a greater probability of 
finding similar remains in the Hallett’s Cove beds than a marine 
fauna. There seems to be only two suppositions which could 
offer adequate conditions for the glaciation of Southern Australia. 
Hither a much higher altitude of the land, with the main moun- 
tain systems restored to the height they possessed before suffer- 
ing the waste undergone during the enormous period separating 
Paleozoic times from the present ; or the extension of the Ant- 
arctic Continent and ice-cap into lower latitudes, with the physi- 
cal contour of the land such as to deflect the Antarctic currents 
to our shores, so that Southern Australia would be climatically 
much nearer the Southern Pole than it is to-day. Either of 
these factors—or, perhaps, both conjointly—may have supplied 
the efficient cause of that refrigeration of climate in South Aus- 
tralia, the evidences of which we have discussed to-night. 
