286 
Genus—FLATTSCHISMA, MeGoj/, 1844. 
(Synop. Garb. Lime. Foss. Ireland, p. 38.) 
Platyschisma ocFLirs, J. de C. Sotoerh j, PI. 15, figs. 3 and 4. 
Trochus ocidus, J. cle 0. Sowerby, Mitchell’s Three Exped. Int. E. Australia, 1838, i., p. 15, t. 2, 
f. 3 and 4. • 
Platyschisina oculuSt Morris, Strzelecki’s Phys. Descrip. N. S. Wales, 1845, p. 286, t. 18, f. 1. 
Euomplmhis oculus, De Koninck, Foss. Pal. Nouv.-Galles du Sud, 1877, Pt. 3, p. 330, t, 23, f. 18. 
Ohs. Two specimens, wliich I am quite unable to refer to any other than this 
species, have been obtained through the painstaking efforts of the late Mr. James 
Smith. Neither is in a good state of pi-eservation, one being only a portion of a 
specimen, whilst the other was evidently much crushed during the life of the shell, and 
naturally repaired, whereby tbe base baa been obliquely pressed inwards, and the 
umbilicus thrown out of place. The body-whorl is, to some extent, channelled or 
flattened along the suture, a feature also visible in some varieties of P. ociilus. 
Loc. and Horizon. Stony Creek, Stanwell, near Rockhampton {The late James 
Smith) — Gympic Beds. 
Plaxysohisma eotunda, Etheridge, PI. 15, fig. 6. 
Phw'otomaria rotunda, Etheridge, Quart. Journ. Geol. See., 1872, xxviii., p. 330, t. 18, f. 3. 
Sp. Char. Shell turbinate or trochiform, with four whorls ; apex slightly 
depressed ; aperture suboval or subangular. Whorls completely rounded and concentri- 
cally striated, with numerous close-set costm, which are crossed diagonally from the 
mouth backwards by very fine lines, giving the shell a reticulate appearance. Base 
slightly convex. Umbilicus very small or obsolete. Sinus scarcely distinguishable. 
(Etheridge.) 
Ohs. This shell appears at first sight to be smooth, the ornamentation being 
microscopic, yet definite ; on a portion only of the shell is there structure remain- 
ing. In form, size, and general aspect, P. rotunda resembles P. granulata, De 
Kon., but the sculpturing of the shell, and the band-like sinus, remove it from 
that species. P. rotundata, PhilL, in the rotundity of the whorls and other 
minor points, somewhat resembles it, but our species is much less acute in the spire. 
(Etheridge.) 
Platychisma rotunda possesses a most suspicious resemblance to P. oculus, but 
tbe figure of the former affords no evidence of an umbilicus, and its umbilicus is even 
described as very “ small or obsolete.” If there is no umbilicus, or, on the other hand, 
if the shell really has a band and sinus, it cannot be a Platyschisma,^}^^ generally it very 
closely resembles this genus. 
An impression of a much smaller shell, but one otherwise resembling P. rotunda, 
has been collected by Mr. C. W. De Vis in the Rockhamjiton Beds. The spiral striae 
mentioned in the above description are not visible, but the diagonal lines are very 
apparent, and are more or less sigmoidal. On the whole it very much resembles a young 
condition of Platyschisma rotunda. 
Loo. and Horizon. Cracow Creek, Dawson River, Lat. 25° 20' S., Long. 150° 
15' E., approximately (The late E. Laintree) — Middle or Marine Series, Bowen River 
Coal Field; Rockhampton District* (C. W. Be Vis; Colin. De Vis)-— Gympie 
Beds. 
See note, p. 199. 
