50 
primario angulos 70-80° formantibus, paullo arcuatis, laqueos margine sub- 
parallelis ; ncrvis tertiariis angulo recto exeuntibus ramosis, dictyodromis. 
Obs. — An interesting leaf, which is distinguished from most of the 
fossils from Dalton, not only as regards its size, hut also as regards its much 
more delicate texture. It shows, perhaps, scarcely half the length of the leaf 
to which it belongs ; the margin is entire, the apex abruptly acuminate. The 
venation is hrochidodromic, and shows a comparatively thin, although upon 
the whole prominent, straight, and towards the apex gradually tapering 
midrib. The numerous secondary veins are at almost right angles to the 
midrib ; they are, however, most divergent at the point of insertion, and in 
their further course slightly arcuate, forming loops; the loops being almost 
parallel to the margin. The right-angled tertiary veins branch into a loose 
net. (See the enlargement of the venation, Dig. 4 a.) 
The characters given agree best with the leaves of various Apocynacese, 
with which, however, the fossil does not correspond sufficiently to be placed 
under a definite genus of that order. As regards the numerous and almost 
right-angled secondary veins and their marginal loops, the thinner midribs 
and the more delicate texture, it agrees best with Ochrosia (compare O. 
maculata, Jaccp, Ettingsliausen, Blattskelete der Dicotyledonen, PI. XXVII, 
fig. G), as regards the tertiary veins with Alstonia, and with reference to the 
peculiar divergent insertion of the secondary veins with species of Lynopogon. 
At present, therefore, I believe that the fossil should be included in the genus 
A pocynophyllum. 
Among hitherto described species of that genus, Apocynophyllum 
Heinwardtianum , Gocpp., from the Tertiary Elora of Java, comes nearest to 
our species, but differs in the stronger texture, the strong midrib, and the more 
prominent marginal loops. 
I dedicated the species to my highly esteemed friend, Mr. IX. Etheridge, 
junior, Assistant Curator of the Geological Department of the British Museum, 
London.* 
Locality and Horizon. — Dalton, near Gunning; in hard siliceous grit, 
reposing on Silurian rock. 
* [Now Palaeontologist to the Department of Mines and the Australian Museum, Sydney.] 
