152 TEMPSKYA. 



vesting coat of carbonaceous matter of -jV to -jV inch in thickness, 

 such, e.g., as is represented in a woodcut on page 173 of Fitton's 

 paper. The largest specimen is described as having a length of 

 9 feet. My attention has been drawn by Mr. Carruthers to this 

 coaly covering in certain specimens of Tempskya Schimperi, which 

 he has himself examined in situ in the Isle of Wight ; he is of 

 opinion that the coal may be looked upon as the carbonized remains 

 of some peripheral or external tissues, the more internal portions 

 having been more or less perfectly preserved by mineralization. 

 No doubt we may regard the coal as the carbonized remnants of 

 some external tissues, but there hardly seems any adequate reason 

 for concluding that the tissues, thus reduced to a condition of 

 coal or lignite, were originally of a different nature to those 

 underlying structures which have been partially preserved in, 

 the process of fossilization. Corda 1 figures and describes four 

 species of Tempskya, but it is by no means easy, from an inspection 

 of his figures, to grasp the points of difference on which the 

 specific characters were founded. He considers T. Schimperi to 

 consist simply of a mass of roots and petioles imperfectly preserved. 

 Dunker 2 refers to specimens of the same plant from North Germany 

 as representing the stem of some unknown Monocotyledon. 



In a later work Mantell 3 quotes Eobt. Brown's opinion that the 

 structure of Endogenites erosa suggests an approach to the Cycadea. 



Cotta's 4 figure of what he calls Porosm marginatm shows what 

 are no doubt numerous small roots, and apparently a few petiole (?) 

 axes. 



The specimen figured by Schenk 5 was found in the Hastings 

 Sands of Neundorf near Hannover, and is regarded by him as 

 identical with Mantell's specimens from the English Weald. This 

 writer prefers to look upon Tempskya Schimperi as an imperfect 

 specimen of part of a complete stem, and not merely a mass of 

 roots and petioles as described by Corda ; he recognizes the fern 

 character of the vascular bundles. Schenk speaks of the numerous 

 small and circular vascular bundles as surrounded by sclerenchy- 



1 Flor. Vorwelt, pp. 81-83, pis. Iviii. and lix. 



2 Wealdenbildung, p. 17. 



8 Geol. Excurs. I. Wight, p. 288. 



4 Dendrolithen, pi. viii. figs. 4 and 5. 



8 Palseontographica, vol. xix. pis. xlii. and xliii. 



