350 P. M. DUNCAN ON SOME FOSSIL REEF-BUILDING CORALS 



them how to account for the occurrence of fossils indicative of such 

 a warm climate in such high northern latitudes ; for the absence of 

 cold must be accounted for to explain the growth of these trees in 

 that spot. 



Prof. Ansted maintained that the geologists had certain natural- 

 history facts on their side with regard to the occurrence of fossils 

 near the poles ; it remained, therefore, for the astronomers and 

 physicists to find a new theory to account for these facts. 



Prof. Green thought that the astronomers should be asked if the 

 change of axis was a possible explanation, and to calculate what 

 would be the result of a change in the distribution of land and sea, 

 and how would such a change affect the position of the poles. The 

 question was one of mechanics. 



Mr. Sorby considered that the amount of heat and light received 

 from the sun should also be taken into account, and the fact that 

 this may have varied at different periods. 



Sir Antonio Brady stated that there were many facts which 

 tended to prove that the sun had varied in heat &c. ; but the sun 

 had probably little to do with the warmer climate of the poles in 

 past ages. The heat of the earth in its various stages of cooling 

 would be sufficient to account for these changes of climate on the 

 surface of the globe. 



Prof. Ramsay could not agree with the last speaker in thinking 

 that radiation in cooling would produce any palpable effect on the 

 surface of the globe. So far from there being any proof that the 

 climate had been gradually growing colder from the earliest times 

 down to the present date, there was every evidence to show that 

 glacial periods had recurred at different periods in past time. Dr. 

 Duncan and Mr. Evans had merely given suggestions, but had not 

 attempted to solve the problem. The poles probably occupied the 

 same position in Miocene times that they do to-day. Darwin and 

 Dana were both agreed in thinking the present continents to be of 

 extreme antiquity. Great elevations of land had taken place prior 

 to the Miocene epoch. The Alps and the Himalayas were both 

 pre-Miocene, and were probably higher in pre-Miocene times than 

 at present, having been subjected to great denudation. 



Mr. Gwyn Jeffreys pointed out that certain species of shallow- 

 water mollusca now found in the Arctic Ocean had formerly in 

 post-Tertiary times lived as far south as Sicily. 



Dr. Wright remarked that there was a wonderful similarity be- 

 tween the Miocene echinoderms from Australia and those found at 

 Malta. 



Prof. Morris considered the abundance of echinoderms belonging 

 to the Spatangoid group in these Australian beds to be very inter- 

 esting. The feature presents itself in the New-Zealand Tertiaries, 

 where forms allied to Arachnoides occur. The distribution of these 

 echinoderms in New Zealand was excessively complex and difficult 

 to understand. There was a remarkable similarity between the 

 Miocene floras of Greenland and Central Europe ; and the question 

 to be asked was, Did they spread over a continent formerly existing 



