446 A LARGE EQUISETUM FROM THE HAWKESBURY SANDSTONE, 



one of the best means of recognising the genus. In the absence 

 of any of these charactei's, however, differentiation between the 

 genera is by no means easy. The same remark also applies to the 

 genera PhyUotheca,Schizoneura, at least to some extent, and perhaps 

 to Vertehraria also. In the first-named there is a sheath similar 

 to Equisetum, but it is prolonged into long linear leaves diverging 

 from the stem in whorls. In Schizoneura we again meet with a 

 sheath, and a " number of longitudinal leaflets with a central vein 

 attached along their margins."* This sheath then undergoes a 

 peculiar subdivision, which need not be further referred to. As 

 regards Vertehraria, the peculiarities of its stem at once distinguish 

 it. 



The portion of the stem now before us is six inches long, and in 

 its present compressed state nearly four in width, tapering at the 

 lower or distal end to an obtuse point. Within the length of the 

 specimen there are eight internodes, the foremost but one, and 

 best preserved, being nearly one and a-half inches long. The 

 lower or distal internodes are half an inch long. The rate of 

 deci-ease of the stem is but gradual, and the amount of curvature 

 very little. The nodes are now represented by narrow impressed 

 lines of a dark colour, and here and there are interrupted in their 

 course by oval cicatrice-like scars. The vertical costse, or ribs, 

 are narrow, now merely dark coloured lines, usually about one- 

 sixteenth of an inch apart, and invariably opposite oq contiguous 

 internodes. 



So far as I am aware the genus Calam.ites has not been met 

 with in the Permo-Carboniferous Coal Measures of N. S. Wales 

 at all, nor is it satisfactorily known from the associated Marine 

 beds, although the late Prof, de Koninck recorded f C. varians, 

 Germar, as occurring in N. S. Wales, but without definite locality. 



Calamites has certainly never been obtained from any of our 

 higher Secondary beds. Nor, am I aware of any recorded occur- 



* Feistmantel, Pal. Indica, Gondwana Flora, 18S0, iii., No. 2, pt. 1, p. 59. 

 t Foss. Pal. Nouv. Galles du Sud, 1877, pt. 3, p. 142. 



