53 



THE LAUNCESTON TERTIARY BASIN. 



Second Paper by M. M. Johnston. 

 [Read 11th August, 1874.] 



Having devoted some spare time to the further investiga- 

 tion of the Launceston Tertiary Basin, the taking stock of 

 whatever information I have been enabled to glean since my 

 last communication, may not be uninteresting to the members 

 of the Royal Society. 



The association of the fossil pines (so abundant throughout 

 the district) with various leaf impressions of other exogens is of 

 considerable importance, as it favours the inference that they 

 belong to the same period. Some, however, who are entitled 

 to respect, hold a different opinion, and we must confess that 

 although the leaf impressions referred to are, undoubtedly, 

 recent, and belong to the system in which they are now found, 

 it is by no means conclusive that the silicified pines, especially 

 the waterworn specimens, are of the same age. It is quite 

 possible that much of the latter may be the re-wash of a 

 former period. Without committing myself, I may venture 

 to state that my recent discoveries at Stevenson's Bend, and 

 Corra Lynn, tend to confirm the opinion that they are of 

 about the same age as the Breadalbane lignites, at any rate, 

 not older, as the tuff ox ivacke overlying the lignite there, con- 

 tains the remains of a perfect forest of pine trees which, 

 certainly, could not have been washed from an older rock, 

 and no evidence of a foreign matrix can be discerned. 

 Further, as there are numerous instances of the smaller 

 branches maintaining their natural connection with the parent 

 stem, it is almost conclusive that they have not been removed 

 from an older rock, but are really exposed in the original 

 matrix. 



Corra Lynn Agglomerate. 



In an exposed cliff section, on the North Esk, near to 

 Corra Lynn, figured by me in a former paper (No. 33), I 

 recently discovered the pine Banksia and two other undeter- 

 mined woods.* One of the latter shows in a transverse 

 section, large porous vessels scattered irregularly, as in the 

 Eucalyptus. The vertical tangential section, however, is very 

 different, the medullary ray bundles being very large, verti- 

 cally elongated, and have the several rows of cellular fibre 

 presenting a square instead of a roundish net work. Of the 

 other undetermined wood, I have not had time to make a 

 proper transverse section, but I have satisfied myself that it 



* I am indebted to my friends, Messrs. A. Weedon and T. Atkinson, for the di*« 

 eovery of two of these woods at Corra Lynn. 





