20 INCESTS SEDIS. 



A very similar fossil has been figured by Fontaine from the 

 Potomac beds of Baltimore as "an undetermined plant"; 1 his 

 specimen is smaller, but very similar in form ; it shows a circular 

 orifice in the centre, a character not noticed in the English 

 example. The Potomac fossil is described as more like a leaf- 

 sheath of JEquisetum than anything else. Ettingshausen 2 has 

 figured a small object from the Wealden of Zobing, described as 

 a u Patellenahnliches Gebilde," which may be compared to our 

 figured specimen. In the genus Phyllotheca there is a certain 

 amount of resemblance to the present specimen in the form of 

 the leaf-sheaths. Zigno's figures of Phyllotheca equisetiformis, Zig., 3 

 represent stems with nodes clasped by leaf-sheaths deeply divided 

 into acute and slightly incurved segments. In the case of a 

 detached leaf we should expect, however, to have a circular 

 structure with a central aperture. In a leaf-sheath of Phyllo- 

 theca Schtschuraroskii, Schmal., 4 from the Russian Jurassic rocks, 

 there is also a certain similarity as regards size and general form. 



Specimen B. PL I. Figs. 8 and 9. V. 2328. 



Ecclesbourne. Rufford Coll. 



This specimen consists of a repeatedly branched structure bear- 

 ing small and closely arranged leaves ; the axes of the branches 

 are distinguished in several places by the presence of a white 

 mineralization substance in the form of fine longitudinal lines, 

 suggestive of a slender and woody central cylinder; the general 

 habit is somewhat stiff ; length 3 cm. 



Mr. Carruthers, to whom I showed the specimen, recognized a 

 resemblance to the sporangiferous branches of some of the Lycopo- 

 dium Phlegmaria group, 5 and pointed out the possibility that the 

 small carbonaceous patches shown in Fig. 9 in the axis of the left- 

 hand leaves may be the remains of sporangia. In addition to these 

 black patches the enlarged piece of a branch (Fig. 9) shows the 

 pointed and slightly falcate leaves, which appear to occur in two 



1 Potomac Flora, p. 276, pi. clxxiii. figs. 11 and lla. 



2 Abb., k.-k. geol. Reichs. vol. i. Abth. iii. No. 2, p. 32, pi. iii. fig. 20. 



3 Flor. foss. Oolit. vol. i. p. 60, pi. viii. fig. 5a, etc. 



4 Schmalhausen. Mem. Ac. Imp. St. Petersbourg, ser. vii. vol. xxvii. No. 4, 

 1879, pi. vi. fig. 3. 



5 Baker. Fern-allies, p. 19. 



