1^. 



2 



3. 



2-44 



1-9 



1-44 millims 



1-28 



1-0 



•9 



1-9 



1-5 



1-2 „ 



160 PEOCEEDINGS OF THE GEOIO&ICAL SOCIETY. [Eob. 6, 



Cp.ASSATELL.i COMPLICATA, SpOC. IIOV. PI. IX. fig. 8. 



Shell oblong', very much compressed, very ineqiiivalve, the poste- 

 rior side truncated ; anterior side rounded ; lip smooth or crenulated ; 

 lunule ill-defined; umbo subacute, ornamented with acute costse, 

 •which diverge from the umbo, the angles of the ribs succeeding each 

 other in an oblique direction, a little anterior or posterior to the 

 middle line of the valve ; the set of costse directed towards the an- 

 terior side are slightly reflected ; the series directed towards the 

 posterior side are straight, the superior costae of which form another 

 group of diverging ribs ; the angles of these are more acute and are 

 directed from the umbo ; a few straight costae occupy the remaining 

 portion of the anal area, and denticulate the hinge-line, which is 

 straight. 



Dimens : — 1. 



Length (entire) 3-17 



Breadth 1-7 



Length of posterior side . . 2-46 

 The diverging ribs of this species connect it with G. Eobinaldina, 

 D'Orb. *, of his "^ Keocomien inferieur " of the Parisian basin, and 

 serve to distinguish it from all other species of the genus. (7. 

 complicata differs from its European representative in its straighter 

 hinge-line, its truncated posterior side (in C. Rohincddina the anal 

 side is sHghtly acuminated), in its more arched anterior side, and in 

 having only about one-half the number of ribs. These two species 

 present in their remarkable ornamentation a wide departure from the 

 genus, the greater number of species of which have smooth shells ; 

 in others they are concentrically furrowed. 



Species of the genus characterize tropical seas, and they are well 

 represented in the Tertiary deposits in various parts of the northern 

 hemisphere. During the Cretaceous epoch they appear to have been 

 few in number, as not more than eight or nine are known ranging 

 upwards from the lowest marine bed of that system. 



The restricted range of the genus Cmssatella favours the supposi- 

 tion that the Secondary fauna of Uitenhage may be of Cretaceous 

 age ; but the opinion that too much value must not be placed on an 

 isolated case is confirmed by the discovery of a true Crassatella in 

 the Inferior Oolite of Eodborough, near Stroud, England ; and though 

 it be not of the type to which G. complicata belongs, yet the value of 

 the genus as evidence of a Cretaceous facies is thereby lessened. 



Log. Sunday's ^iygv {Atlierstone); and in a yeUowish-grey sandy 

 sheU-rock at Prince Alfred's Eest {Rubidge), 



Cypeicaedia JSTiveniana, spec. nov. PL YII. fig. 10. 



Shell elongated, subtrigonal; umbo placed anteriorly to the 

 middle of the valve, rather elevated and subacute ; anterior side 

 rounded, its upper margin sHghtly excavated, its lower extremity 

 pointed ; the posterior side slopes obliquely downwards, and has an 



^' Pal. Fran9. Terr. Cret. vol. iii. p. 75, pi. 264, figs. 10-13. 



