324 Miscellanea. 



Dedicated to Sir T. Mitchell, one of the first to make known 

 the existence of fossils in those rocks. 



Pleurorhynchus Australis (M'Coy). PI. XVI. fig. 4. 



Sp. Char. Alfeform or transvei'sely subtrigonal, gihbose, length 

 nearly two-thirds the width ; posterior side forming a compressed 

 narrow wing; anterior face obHquely snbiruncate, convex, 

 divided into three nearly equal tumid compartments by two im- 

 pressed furrows from the beak ; body of the shell and posterior 

 side radiated with rather coarse irregular ridges from the beak ; 

 anterior face finely striated longitudinally. 



This resembles the P. minax (Phil.) in the striation of the anterior 

 face being so much finer than that of the middle or posterior paj'ts 

 of the surface ; it differs in having the anterior face not only much 

 more finely striated, but divided into three parts by distinct furrows ; 

 while from the Cardinm irreyidare and C slramjiilalum (Kon.), 

 which have the anterior face so divided, but smooth, it is distin- 

 guished by this latter character, and also by wanting the mesial 

 strangulation of those species. Length of small specimen 8 lines, 

 ■width I inch. 



Not uncommon of larger size in the sandy schists'of WoUongong, 

 N. S. Wales. 



Allorisma ciirvatum (Mor.). 



Comm.on in the sandstones of Darlington, WoUongong, and 

 Glendon, N. S. Wales. 



Orthonota compressa (Mor.). 

 In the calcareous schists of Harper's Hill, N. S. Wales. 



Orthonota costata (Mor.). 

 Common in the sandstone of WoUongong, N. S. Wales. 



Modiola crasshsima (M'Coy). PI. XV. figs. 2 & 3. 



Sp. Char. Transversely ovate, very gibbose : beaks small, nearly 

 terminal ; anterior side forming a small rounded lobe beneath the 

 beaks, separated from tlie body of the shell by a strong sinus in 

 the ventral margin, from which a shallow concavity runs towards 

 the beak ; posterior side wide ; hinge-margin elevated, fom'-fifths 

 the width of the shell in length, compressed, angulatcd, posterior 

 end broadly rounded; ventral margin convex ; shell very thick ; 

 surface with a few concentric waves of growth, and marked 

 towards the posterior inferior angle with a few distant obsolete 

 ridges, extending obliquely from the beaks. 

 Length 5 lines, width 1 inch 7 lines, height of cardinal angle 



11 lines (occasionally Scinches wide). 

 Not uncommon in the schists of Harper's Hill, N. S. Wales. 



Pachifdomus carinatits (Mor.). 

 Abundant in the fine sandy schists of WoUongong, N. S. Wales ; 

 more rare in the white rock of Port Arthur, V. D. Land. 



Pachydomiis glohosus (Sow. sp.). 

 Common in the sandstone of WoUongong, N. S. Wales. 



