]02 Carruthers — Secondary Cycadean Fruits. 



Fossil wood, leaves, and fruits, afford the means of determining 

 the existence of vegetables during any geological period. 



The trunks and foliage of Cycade(B are so remarkable that fossil 

 fragments of them can, as a rule, be determined with certainty. The 

 trunks are generally short, and composed externally of the basis of 

 the leaves, while internally they consist of a large medulla, either 

 simple or traversed by numerous vascular bundles, and surrounded 

 by one or more woody cylinders. The trunks from Purbeck, which 

 Buckland named Oycadeoidea. specimens of which have also been 

 foimd in the Oolite of Helmodale, Sutherlandshire, by Mr. Ch. W. 

 Peach, and those from the Wealden, named Clathraria by Man- 

 tell, have all the characters of Cycadean stems. The leaves are 

 remarkably uniform in the modern representatives of the order. 

 With a single exception they are pinnated, hard, and woody, and 

 the leaflets have fine, simple parallel veins. The genus Stangeria 

 has paralled forked veins like those of a Lomaria, and we fear 

 that this anomalous structure has induced palaeontologists to place 

 among the GycadecB some fossils which would more correctly be 

 referred to Ferns. The cones of Cyaadece are less frequent fossils 

 than either the leaves or the stems. In a former paper (Vol. III., 

 p. 535), I exhibited the characters by which Cycadean cones are 

 distinguished from those belonging to the Conifer cb. I may here 

 further add that the scales of the Cycadean cone have a much simpler 

 arrangement than in that of Coniferce. In Cycadece the scales are 

 arranged either in a vertical series, as in the female cone of Zamia, 

 or the secondary spirals consist of only two series, and the amount 

 of obliquity in their direction is the same whether they wind to the 

 left or to the right, as in Encephalartos. 



Corda, in Eeuss's " Die Versteinerungen der Bohmischen Kriede- 

 formation," says he has never seen any real fossir Cycadean fruits, 

 except the two that he there describes. These are Microzamia gibba, 

 a female cone, unlike any recent Cycadean cone in having from 

 three to six seeds supported by each scale, and Zamiostrobus famili- 

 aris, which from the form of the scales, and from having vascular 

 bundles scattered through the medulla of the axis, he considers a 

 true Cycad, and probably the male cone of the former species. 

 Endlicher established the genus Zamiostrobus for a cone he believed 

 to be Cycadean. But as I have formerly shown (1. c, p. 536), 

 it was founded in error, and great confusion has since been created 

 by making it the receptacle for cones, whose affinities could not be 

 made out. Of the seven species now placed in the genus, I have shown 

 four to be Coniferce. What Z. Fittoni, Ung., may be or may not 

 be, it is impossible to say from Fitton's drawing in the " Geological 

 Transactions," 2nd series, vol. iv. t. xxii. f. 11. Fitton had a longi- 

 tudinal section of it made, but he tells us (1. c. p. 349) that it " did 

 not exhibit any indication of vegetable structure." In the British 

 Museum there is a cast of a cone belonging to 0. B. Eose, Esq., 

 which corresponds remarkably with Fitton's figure. It was obtained 

 from the Lower Greensaiid at Downham, near Lynn, Norfolk ; but 

 I believe the original specimen has decomposed, like so many pyritic 



