48 
Appendix to the Silueian Species. 
Among tlie numerous imprints of calices of E^ugose Corals that have 
been submitted to me, I have met with several similar to those known as 
Cyatho;phijllum h'mum, elongatum, &c., hut of which the specific diagnosis will 
remain doubtful and incomplete for so long as it is not possible to find 
specimens on which the exact structure of the corals these imprints belong to 
can he studied. Ifor this reason I have refrained from referring to them in 
my work. 
However, I make an exception of an impression which has almost the 
shape of a half-cone, that is to say of a very elliptic cone, which has been 
cut in half along the axis, and which seems to me' to have been formed by the 
removal of a fossil in all respects like Calceola. 
In reality the greater part of the curved surface is covered with small 
radiating ridges, very apparent towards the margin, and beset with small 
granulations scarcely visible to the naked eye, which have been formed l)y 
very small pits at the bottom of the furrows in the calice. The fiat face is 
not ribbed, except towards the lower margin ; these rilis are smooth. On the 
median portion, corresponding to the axis of the cone, is seen a fairly deep 
longitudinal slit, which has been formed by the median sej)tum, usually more 
developed than the others in the calice of Mkizophyllum, to which I refer it, 
because true Calceola are up to the present unknown in Silurian rocks. I 
describe it under the name of Rhizophyllum mterpunctatum} 
Horizon and Locality . — The specimen I have just described and 
illustrated on PI. I, Fig. 10,^ was found in an ochreous argillaceous rock at 
Pock Flat Creek, where several of the species of Trilobites already described 
occur, so that its Silurian age is undoubted. 
It is on a piece of similar rock containing a complete head of Cromus 
Murcliisoni, L. G. de Koninck, that I noticed the impression figured on PI. IV, 
fig. 1. This impression appeared to me to be worthy of notice, because of its 
great resemblance to the form frequently met with in some Devonian beds of 
1 [See also Etlierilge (R., Junr.) — Journ. R. Soc. N. S. Wales for 1880 [1881], XIV, p. 247 ; Lindstroin, 
Bihangk. Vet. Akad. Haiull,. 1882, Vlf, No. 4, p. 29 ; Etheridge (U., Junr.). Records Austr. Mus., 1891, I, No. 10, 
p. 203, pi. 30, figs. 7-15. — IV.S.D.] 
2 [PI. I, fig. 14.— W.S.D.] 
