BY T. W. E. DAVID. 253 



Newcastle Coal-measures Upper Marine Series 



Dempsey Beds Greta Coal-measures 



Tomago Coal-measures Lower Marine Series 



The total thickness of this system is between 10,000 and 11,000 

 feet. 



Glossopteris ranges from near the top of the Lower Marine 

 Series to the top of the Newcastle Coal-measures. 



The oldest fossil plant at all related to Glossopteris at present 

 known to us is represented by somewhat imperfectly preserved 

 leaves in a fine grained sandstone, in the Lower Marine Series, 

 near Lochinvar. 



This horizon is probably over 2000 feet below the top of the 

 Lower Marine Series and the base of the Greta Coal-measures. 

 The leaves, which have not yet been figured or described, appear 

 to resemble Gangamopteris leather than Glossopteris. The lowest 

 horizons from which undoubted Glossopteris has been obtained in 

 New South Wales are (1) near Farley (Stony Creek), West Mait- 

 land, a few hundred feet below the base of the Greta Coal-measures ; 

 and (2) at Nicholson's Quarry on the Hunter River, about three 

 miles above Belmore Bridge, West Maitland. 



In the Greta Coal-measures Glossojjteris is very abundant and 

 is associated with almost equally abundant Gangamopteris, 

 Noggerathiojysis, and Vertebraria. It occurs most plentifully in 

 the clay shales forming the floors and roofs of the productive coal- 

 seams. At Richmond Vale, near East Maitland, as already 

 described by one of us,* Glossopteris leaves have been found with 

 so much of their original organic structure preserved as to be quite 

 flexible. Many of the leaves were rolled up by the mechanical 

 action of water, but after they had been treated for a few hours 

 in glycerine it was found possible to unroll them to their full 

 original length. 



* T. W. E. David. Proc. Linn. Soc. N.S. Wales, 1890, v. (2), Pt. 3, 

 pp. 424-426. 



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