Vol. 52.] GLACIAL ACTION IN AUSTRALIA. 301 



these lithological breaks in the succession of strata is not yet under- 

 stood, but they may possibly indicate a sequence of glacial epochs 

 separated by milder interglacial periods. Possibly glacial conditions 

 in Australia may have been prolonged from late Paheozoic into early 

 Mesozoic time, as may perhaps be argued from the presence of plants 

 of Mesozoic facies, such as Schizoneura and Zeugophyllites, in the 

 uppermost glacial beds of Bacchus Marsh, and also perhaps from the 

 disrupted masses of clay-slates and contemporaneously-contorted 

 current-bedding in the Triassic Hawkesbury Series of New South 

 Wales. 



EXPLANATION OF PLATE XII. 



Horizontal and vertical sections of the Permo-Oarboniferous Glacial Beds 

 at Bacchus Marsh (Victoria). 



Discussion. 



Dr. Blanford referred to the peculiar interest that he took in 

 the paper, as he had, nearly 40 years ago, called attention to the 

 existence in India of rocks similar to those described in Australia, 

 and of the same age, and had suggested a glacial origin for 

 them. He heartily congratulated the Author on his admirable paper 

 and on the conclusive evidence of glacial action now brought forward, 

 evidence so clear that it was doubtful whether a sceptic remained 

 among those who had attended the meeting. The speaker pro- 

 ceeded to give a few details of the progress of discovery in India, 

 and referring to the evidence gradually accumulated from Australia 

 and South Africa, especially noticed how in the Argentine Republic 

 of South America all the peculiar Upper Palaeozoic and Mesozoic 

 floras of Australia — the Carboniferous flora with Lepidodendron and 

 Rhacopteris, the Permo-Carboniferous with Glossopteris and Gangamo- 

 pteris, and the Lower Mesozoic with Thinnfeldia odontopteroides — had 

 been discovered one after another, and how their constant associates 

 in other lands, the boulder-beds, appear to have been found by 

 Prof. Derby in Southern Brazil. He pointed out the connexion 

 between these discoveries and the question of the former distribution 

 of land, and called attention to a recent paper by Mojsisovics, 

 Waagen, and Diener, who showed that while the present contours 

 of the Pacific Ocean were of pre-Triassic age, those of the Indian 

 and Atlantic Oceans appeared to be of later origin. 



Mr. Wickham King and Prof. Bonney also spoke, and the Author 

 replied. 



