247 
The punctse on the exterior of the shells appear as small rugosities scattered at 
random over the surface of the ribs or strise, and intervening valleys, ornamenting these 
shells, but when worn to any extent their perforate character at once becomes apparent. 
They are, in particular, very numerous on the area and deltidium. 
The cardinal process is developed in a high degree* in this species. It extends, 
not only partially under the pseudo-dcltidium of the ventral valve, as described by Mr. 
Davidson * in Ortliotetes crenistria, but completely under it for some distance. In the 
present specimens it is a long, rather shoe-horn shaped, testaceous projection, extending 
either at right angles, or nearly so, from the umbona^ centre of the hinge-line. In one or 
two cases it is quite at right angles, in others it is inclined upwards. In ordinary forms 
of Ortliote.tes orenistria the cardinal process is bidentate at the outer end, but in the 
present ease the terminal expanded bidentation is flanked by a lateral projection on 
each side and always more or less perceptible, but at times much more marked than at 
others, and when so considerably increasing the width of the process. 
These prominent examples of Orthotiies senilis to some extent resemble the 
variety robusta, Hall, figured by Dr. Davidson from Indian Carboniferous rocks, f only, 
in the latter, the ventral valve appears wider across the hinge ; the umbo, however, 
projects upwards and backwards, as in the Queensland examples. 
Loc. and Horizon. Pelican Creek, three-quarters of a mile above Sonoma Eoad- 
erosslng (E. L. Jack ) — Middle or Marino Series, Bowen Eiver Coal Pi eld ; Havilah- 
Byerwin Eoad, one mile south of Eosclla Crock-crossing (E. L. Jack). The geological 
position of this species in the Bowen Eiver Coal Field is both interesting and peculiar. 
According to my Colleague’s notes, the first locality above given is in his Middle or 
Marine Series, while the second locality is iu a marine band, in his Upper or Freshwater 
Series, which is characterised by the predominance of the much-disputed genus 
Gllossopteris, and other so-called Oolitic plants. 
Family— PEODUCTIDiE. 
Genus— JSOJUCTUS, J. Soioerhy, 1814. 
(Min. Con. i., jj. 153.) 
Obs. The Producti of the Eastern Australian area form a peculiar and intei’esting 
group in themselves. The identity of many of the species with those of Europe is, I 
think, vague. We certainly possess Produotus cora, D’Orb., or, at any rate, a form so 
1 e it that I am unable to refer to any difference, whilst other species have from time 
to time been referred by Authors to P. longispinws, P. scabriculus, P . semireticulatus , 
■’■nd others. I have made use of these terms even in the present Memoir, but I feel 
at they are but names used to distinguish some cast or weathered specimen having a 
tancied resemblance to the species in question. Nine-tenths of our Producti are but 
Casts, and therefore very difficult to determine, and it is not until a long and close study 
c such from many localities has been made, that the number of species actually existing 
c^n be put on a satisfactory footing. T’he species, however, arc few, and it is not 
Improbable that this decrease in number has to some extent been compensated for by 
0 increase, both in species and their importance, of the genus Slrophalosia. 
Long research leads me to the belief that great community of form existed 
ttiongst the Producti of Queensland, New South W^ales, and Tasmania, 
to cMy two species of which sufficiently complete specimens have been found 
render their entire examination satisfactory, both are now known to possess an area, 
,'^j ^ily well marked, always certainly jireseut. 
* Mon Brit. Garb. Brach., 1858, Pt. 4, p. 30. 
t Quart. .Tourn. Geol. Soc., xviii., p. 30, t. 1, f. 16. 
