PROCEEDINGS, AUGUST. 



AUGUST, 1890. 



The monthly meeting of this Society was held on Monday, August 12th. 

 The President, His Excellency Sir R. G. C. Hamilton, took the chair. 



NEW MEMBERS. 



Mr. Thos. Whitelegge, F.L.S., Zoologist Australian Museum, was- 

 elected a corresponding member, and Mr. F. Chalk, barrister- it-law, a 

 new member. 



A FOSSIL TREE. 



Mr. James Barnard read a communication which he had received from 

 Mr. S. H. "VVintle in regard to a paper read by Mr. Barnard for him at the 

 June meeting of this year, entitled " Notes on a Fossil Tree found beneath 

 100ft. of basalt at Richmond, Victoria." Mr. Wintle wrote as follows : — 



" I find in the discussion which followed the reading of my remarks by 

 the Vice-President, that Mr. C. H. Grant expressed an opinion that the 

 condition of the wood afforded satisfactory evidence that the basaltic lava 

 which entombed it could not have had a high temperature. A moment's 

 reflection will show that such a conclusion is quite untenable. The degree 

 of heat necessary for molten rock-matter, such as lava, to flow, is laid down 

 by no less an authority on Seismology than Mallet to be from l,900deg. to 

 2,000 deg. Fahr., a temperature sufficient to melt copper. Mr. Grant's 

 opinion as to a low temperature of the basalt at the time it overflowed the 

 tree was based, I presume, upon the fact that the wood displays no sign of 

 being carbonised, or charred, beyond a slight trace at its superior surface 

 at the point of contact with the once molten rock. This feature, I take it, 

 is to be accounted for by the fact that the enveloping fluid lava by 

 excluding the air would effectually prevent an access of oxygen to the 

 wood ; and further, that the surface of the lava-stream, which would come 

 in contact with the tree first, is always cooler than the interior or the base 

 of the stream. I also observe that Mr. Grant regards the basalt (a specimen 

 of which accompanied the example of the fossil wood) as ' diorite,' according 

 to the report referred to. With all due deference I would observe that this is 

 erroneous. It is true basaltic lava of that kind known as Anamesite of 

 Pleistocene Age, and not greenstone, which diorite proper is. The newer 

 basalts, which in Victoria have filled up so extensively Miocene and 

 Pliocene valleys, and river channels, are chiefly vesicular zeolitic dolerites 

 and Anamesites, the former being well represented by the light coloured 

 Malmsbury ' bluestone ' so extensively employed in buildings in 

 Melbourne." 



Mr. Grant explained that he had only referred to the matter as a 

 suppositious case, and that his remarks had been evidently misunderstood, 



Mr. R. M. Johnston said he was not present when the paper was read, 

 but he thought he knew something of the constitution of this fossil. In 

 his work on Geology a section of the book was taken up in describing such 

 fossil trees. From the description given he imagined that this fossil 

 exactly corresponded with those found in the deep leads of Beaconsfield. 

 From the appearance of those fossils it was quite possible that the wood 

 was protected at one time by clay, which formed a protective envelope 

 between it and the overflow of the basalt. The best specimens could be 

 obtained in the railway cuttings at Breadalbane, where a perfect forest of 

 the ancient vegetation of the Mesozoic period was entombed, and destroyed 

 by the scoria and ashes and molten flows of matter from the volcanic 

 eruptions at that time so prevalent in this and some other localities 

 throughout Tasmania. It has been found by mineralogists that if basalt 

 is thrown up by eruptive influence in a state of ashes, and if afterwards 



