24 



new flora began to appear — a flora that was suited to support 

 moderate or less temperature. Notwithstanding the ice- 

 covered part of the Southern Continent the flora spread 

 slowly westward from Australia during upper carboniferous 

 and permian times to reach Indian and South African regions." 

 This flora (G-lossopteris and Gangamopteris, etc.) was 

 referred to at first as " Mesozoic " types, but very strict 

 investigation has now proved them to have existed in Aus- 

 tralasia prior to the close of the Palaezoic era. 



Dr. Waagen concludes : — " The Palaeozoic fauna and flora 

 was that of warm climates. The organisms composing these 

 were not able to endure great changes in temperature. As 

 then, towards the termination of the Palaeozoic times, first in 

 the Southern and later on in the Northern Hemisphere also, 

 the general temperature was considerably lowered, a circum- 

 stance which is proved beyond doubt by the frequent occur- 

 rence of ice-formed boulder-beds, the whole fauna and flora 

 necessarily perished. It was afterwards replaced by a more 

 hardy set of organisms, which, however, by degrees occupied 

 the place previously taken up by the Palaeozoic forms." 



These conclusions of Dr. Waagen are worthy of considera- 

 tion, for the barren conglomerates and mudstones so largely 

 developed above the Penestella Zone in Tasmania, towards 

 the close of the Upper Palaeozoic age, testify of a condition of 

 things which was prejudicial to organic life, and whatever 

 differences of opinion may exist as regards the exact time 

 which the glacial period may have covered, there is no doubt 

 that the hypothesis partly explains the barrenness of the 

 Upper Palaeozoic marine bods and the sudden break which 

 locally exists between the lower and upper coal measures. 



Eoturning from this digression to our section at One-Tree 

 Point. I observed above the conglomerate beds a single 

 band, of limestone about four feet thick, consisting almost 

 entirely of the fossil remains of Stenopora ovata, all the 

 species or which were of an unusually large size. With the 

 exception of silicified trunks of a huge conifer which 

 occurred embedded sometimes in this limestone and some- 

 times in the conglomerate beds, I could find no trace of any 

 other form of life. One of the fossil conifer trunks was over 

 three feet in diameter. Sections showed the pine structure 

 admirably as well as the numerous regular concentric lines of 

 growth. 



From the large number of rings of growth it was evident 

 that the tree was of considerable age when it was entombed 

 in the calcareous mudstones of One-Tree Point. 



For one hundred feet above the Stenopora band the mud- 

 stones were more argillaceous, but devoid of fossils or 

 nearly so. 



