CONIFERAE, 67 



other forms described as belonging to this genus, one from the Coralline 

 Oolite of St. Mihiel, the other from the Lower Oolite of Siberia and known 

 only in leaf-fragments, can scarcely be considered to be satisfactorily 

 determined. 



The remains from the Coal-measures, which are at present styled 

 Dicranophyllum after Grand' Eury l and are still little understood, can like 

 the preceding genera be compared with Salisburieae only on the strength of 

 their bifurcated leaves. They must be briefly noticed here on account of 

 this connection, though they should properly have been referred to the last 

 section of Coniferae. The Dicranophyllae, figures of which are to be found 

 in Renault 2 and Zeiller 3 as well as in Grand' Eury, are represented by 

 portions of thick branches with spirally arranged leaves and short inter- 

 nodes, and with their surface marked out into rhombic areolae closely 

 crowded together and raised in the centre, like those of Lepidodendrae, 

 and each giving rise to a leaf. The leaves are narrow needles, repeatedly 

 and dichotomously branched, and on the older branches are usually strongly 

 recurved. I have been able to satisfy myself with respect to these charac- 

 ters by personal examination of many fine specimens at the Ecole des Mines 

 at Paris. 



Of the genera still to be considered some are probably connected with 

 the great series of Araucarieae, though we cannot say exactly to which of 

 the different types in that series they belong ; the systematic position of the 

 rest is quite unknown. We must hope that further discoveries will enable 

 us to explain them. 



The best-known of all extinct genera of Coniferae is Voltzia, Schpr, 

 a form characteristic of the Trias and represented in the Permian formation 

 also by two species. The cones of Voltzia, which are frequently found 

 whole and even attached to the branches (see figures in Schimper* and 

 Geinitz 5 ), have the general habit of those of Abietineae ; they are cylindrical 

 and composed of closely crowded spirally arranged scales, which appear 

 ultimately to spread apart from one another. The stout woody scale 6 

 narrows below into a tolerably long stalk ; the flat expansion divides above 

 into five or three obtuse terminations, on the back of which a corresponding 

 number of striated median keels descend to the point of attachment of the 

 stalk and there form a cushion-like elevation. On the upper inner side may 

 be seen in very well-preserved specimens a roundish areola inclosed by a 

 sharp keel-like ridge, to which are attached the edges corresponding to the 

 margins of the lobes. This areola is the plane of insertion of the dependent 

 seeds, which are probably always three in number, though sometimes only 

 two are present standing right and left ; in the latter case the median seed 



1 Grand' Eury (1). a Renault (2), vol. iv, t. 4, f. 9. 3 Zeiller (3), t. 26, f. I. 4 Schimper 

 (3), t. 14. * Geinitz (2), t. 5. Solms, Graf zu (1), and Geinitz (2). 



F a 



