418 MR. J. S. GARDNER ON ALNUS RICHARDSONI. 
allied to Casuarina; but subsequently Dr. R. Brown suggested 
to him that their affinities were rather with the Australian Pro- 
teaceous genera Petrophila and Leucodendron ; and the genus 
Petrophiloides was consequently founded to receive them. The 
scales were thought to be confluent, surrounding “deep cells with 
semicireular mouths," or *empty cells remaining after the ope- 
ration of dehiscence ” *; but these cells are actually cavities left 
by the decay and removal of the true scales of the cone, while 
the supposed scales are amorphous pyrites which has infiltrated 
into the interstices and enveloped the seeds. The form of the 
seed could not, however, be assimilated with that of any of the 
Proteaces ; and it is certainly strange that the minute examina- 
tion they were subjected to did not lead to a better apprehension 
of their true structure. Denuded axes of the cone led to the 
foundation of other, and seedless species. In 1851, Ettings- 
hausen t, believing he had found the same species at Monte 
Promina, revised Bowerbank's work, and pointed out that five of 
the supposed species from Sheppey were specimens of the same 
in different states of preservation. This view was endorsed by 
Schimper f and subsequent authors. 
In 1871 Lyell had occasion to figure them, and submitted them 
to Carruthers, who confirmed Robert Brown's view as to their 
Proteaceous origin$. Their determination remained, in fact, un- 
challenged until 1879, when Ettingshausen transferred them to 
Sequoia, changing the specific name to S. Bowerbankii; but 
since no reference to it or description occurs in the text, it is im- 
possible to appreciate the motives which induced the transfer ||; 
and 1 believe the Professor is now inclined to agree in their re- 
ference to Alnus. Finally, Saporta, to whom I sent specimens, 
without committing himself to any decided opinion, counselled 
me to compare them with Dammara. Although I felt that all 
these references were unsatisfactory, and had decided to omit the 
species from the Paleontographical Society's work on the Eocene 
Conifer of Great Britain, I can claim no particular credit in the 
matter ; for it did not occur to me to compare them with Alnus 
* L. c, p. 45. t ‘Der Eocene-Flora von Monte Promina,’ p. 17: 
t Schimper, * Pal. Végétale, vol. ii. p. 784. 
$ * Student's Elements,’ Lyell, 1871, p. 240. “Carruthers having examined 
them, tells me that all these cones from Sheppey may be reduced to two species 
which have an undoubted affinity to the two Australian genera above mentioned ; 
although their perfect identity in structure cannot be made out." 
|| Proc. Roy. Soc. 1879. 
