DESCRIPTION OF SPECIES. 51 



shown, being slender, and immersed in the thick leaf-snbstance of the pinnules, but 

 apparently as follows : Midrib slender, and dissolving into branches at the summit. 

 Lateral nerves delicate, the lowest twice forked, the upper once forked. 



This plant had a very strong principal rachis. The specimen repre- 

 sented in Plate XXVI, Fig. 5, seems to be a fragment of a very long pri- 

 mary pinna rather than frond. The rachises of the ultimate pinnae are also 

 very stout and rigid in comparison with the size of the pinnules. The 

 plant may well have been arborescent. The pinnules must have been of a 

 thick and leather-like consistency, for they leave a considerable film of coal 

 on the rock and cause a distinct depression in it. They are, as is usual 

 with thick pinnules, when found on soft shale, convex on the upper surface 

 to some extent. The nerves being slender, and immersed in the substance 

 of the pinnules, cannot be seen with distinctness. They appear as given in 

 Fig 5 a, which represents enlarged pinnules of Fig. 5. Plate XXVII, Fig. 

 3, represents a specimen which shows a face of the principal rachis the 

 opposite of that seen in Plate XXVI, Fig. 5. The plant seems to have had 

 on one face of the principal rachis, perhaps the upper one, a depression or 

 channel, and on the opposite face a strong ridge corresponding to the chan- 

 nel on the other side. I know of no previously described plant with which 

 this could be identified, or indeed which closely resembles it. 



Formation and locality. — Found only at Clover Hill, in strata probably 

 connected with the upper series of small coal seams, and here very rare. 



Cladopblebis microphylla, spec. nov. 



Plate XXVII, Fig. 2. 



Frond bi- or tripinnatifid. Principal rachis slender, ridged on one side. Ulti- 

 mate pinnae alternate, long, slender, and linear-lanceolate. Pinnules united at the 

 lowest part of the base, subquadrate and falcate, rather thick in consistency, and 

 alternate. Nerves very distinct and prominent. Middle nerve stout at base, and 

 splitting up into branches about midway the length of the pinnule. Lateral nerves 

 all once forked from near their insertions. 



The nervation of this plant in its tendency to flabellate divergence 

 approaches that of the Acrostichides species, which have a rhombic or sub- 

 quadrate shape in the pinnules. In the shape of the pinnules this plant 

 resembles them, but the nervation is less complex, the branching of the 

 lateral nerves being less copious. The shape of the pinnules is also some- 



