445 



A LARGE EQUISETUM FROM THE HAWKESBURY 



SANDSTONE. 



By R. Etheridge, Jun. 



(Palaeontologist to the Australian Museum, and Geological 

 Survey op New South Wales.) 



(Plate XVII.) 



At a Meeting of this Society, held on May 28tli, Dr. J. C. Cox 

 exhibited* a remarkably fine example of the basal portion of an 

 Eqnisetaceous plant from the Hawkesbury Sandstone of North 

 Shore, Port Jackson. It consists of eight internodes forming the 

 obconical basal termination of the stem. As this peculiar reversed 

 cone-like base occurs both in Catamites and Fquisetimi,j it becomes 

 important to investigate the matter of its identity closer, especially 

 as it has a strong bearing on the question of the age of the deposit. 



The Calamites have a greater analogy with the Equisetums than 

 with any other plants, f but are distinguished by possessing verti- 

 cillate leaves entirely free, or confluent at their bases, and by the 

 presence of clusters of sporangia similar to those of the Lycopods.§ 

 In the Equisetums, on the other hand, the internodes of the stem 

 are each terminated superiorly by a verticel of leaves united into 

 a lobed or regularly dentate sheath, || which is persistent,1I and is 



* Abstr. Proc. Linn. Soc. N. S. Wales, 2Sth May, 1890, p. iii. 



t Schimper, Traitt^ Pal. V6g., 1869, I., p. 257. 



X Grand 'Eury, Flore Carb. Depart, de la Loire, 1877, pt. 1, p. 12. 



§ Schimper, loc. cit., p. 291. 



il Schimper, loc. cit., p. 255. 



IT Renault, Cours Bot. Foss., 1882, pt. 2, p. 157. 



