344 AUSTRALIAN, SOUTH AFRICAN, AND INDIAN COAL-MEASURES, 



the blank period in which the disappearance of the Glossopteris 

 flora took place was one of extreme or severe climatic conditions, 

 accompanied by development of Glacial phenomena either gener- 

 ally or under local conditions. 



Tasmania. 



In Tasmania we find no Lepidodendron beds, nor any other 

 record of upper Devonian or lower Carboniferous. The marine 

 beds of Easlet'n Tasmania, with Productus hrachythoirus, &c., 

 and evidence of Glacial action (Bruni Island and elsewhere), are 

 classed by Mr. Johnston as equivalents of our Lower Marine 

 series, with which they sufficiently correspond. But the Mersey 

 (or Lower) Coal Measures, with GlossojMris (.?), Gaiigamopteris and 

 Noeggerathioijsis spatliulata^ etc., seem to correspond rather with 

 our Middle and Upper Coal Measures, than with the Lower or 

 Greta Coal, with which our author correlates them. If so, 

 these Tasmanian " Lower Marine " beds may represent the whole 

 of our Lower Coal Measures and "Marine" beds; and the 

 Mersey Coal Measures, our "Middle and Upper Coal Measures." 

 But the Tasmanian " Upper Coal Measures " are plainly the 

 same as the Clarence River and Ipswich beds, in all of 

 which Glossopteris, previously so abundant, disappears for ever. 

 A doubtful case of G. linearis and G. morihunda is indeed 

 reported from some of these Upper Coal Measures in Tasmania, 

 just as Mr. Jack mentions another species still surviving in the 

 Burrum basin. But otherwise the fossil flora clearly indicates 

 this identification, which extends even as far as South Africa, 

 where the Stormberg beds contain the very same species, as 

 successors to the same species C?) of Glossopteris.'^ 



* Since writing the above I have received a note from my brother, Mr. 

 Stephens, M.A., F.G.S., of Hobart, mentioning that a fossil heterocercal 

 Ganoid, probably a species of Palceoniscus though in imperfect preserva- 

 tion, has just been discovered in the Knocklofty Sandstone, belonging to 

 the highest formation of the Upper Pakeozoic marine beds in the south of 

 the island. The identification of this fossil will be looked for with some 

 interest. Its occurrence, however, is some evidence in favour of a fluvia- 

 tile origin for this sandstone, which may possibly, like the Hawkesbury 

 beds, be ultimately relegated to a later period than was originally thought 

 probable. 



