the age of the boulder-beds in the deposition of which ice action is believed 
to have been concerned. Much stress is laid upon the occurrence of these 
boulder-beds as evidence of their contemporaneity ; and Professor Eeistmantel 
accordingly adduces it in support of his correlation of the different formations 
in the above-mentioned countries. I am of opinion, however, that too much 
stress has been laid upon this point and that this correlation must for the 
present he regarded only as provisional. I have closely examined the boulder- 
beds of Bacchus Marsh, in Victoria, and those of the Upper Marine Scries of 
Greta and Branxton in New South Wales, and consider that their con- 
temporaneity is extremely doubtful. 
This question leads into a wide field for investigation, and it is well 
that it has been here introduced, for I trust that it will engage the attention 
of many geological observers. 
I may mention that the plates illustrating this Memoir were carefully 
drawn under the personal supervision of Professor Peistmantel. 
I have added foot-notes on certain stratigraphical points to pp. 28, 41, 
and 73, bearing my initials. 
I have the honour to he, 
Sir, 
Your obedient servant, 
C. S. WILKINSON, 
Geological Surveyor-in- Charge. 
IIarrie Wood, Esq , J.P., 
Under Secretary for Mines. 
