150 PEOCEEDINGS OP THE GEOLOGICAL SOCIETY. [Feb. 6, 



d. Description of some Fossils from tJie Jurassic Strata, or ^' XJitenliage 

 Formation,'^ on the Sunday's and ZwartJcop Rivers, South Africa^ 



Ammonites stjbanceps, spec, no v. PI. YII. figs. 3 «, 3 6. 



Shell small, somewhat compressed, deeply umbilicated. Whorls 

 4, narrow, depressed, inflated laterally by the development of the 

 tubercnlose costae. Last whorl ornamented with ten tubercules; 

 ten costse arise from the inner margin of the whorl; these are 

 directed slightly forward, and bifurcate or trifurcate from a salient 

 pointed tubercle in the middle line of the whorl ; the ribs proceed- 

 ing from the tubercle are inflected forwards, and interrupted upon 

 the middle of the back, terminating there in a slightly pointed 

 tubercle, but are otherwise continuous with a similar bundle of ribs 

 developed on the opposite side. Back convex, with a smooth, shal- 

 low furrow in the middle. Mouth large, rounded. 



Dimensions. Diameter '75 inch ; diameter of outer whorl -3 inch ; 

 thickness of outer whorl '3 inch. 



Observations. — It is doubtful whether this be not a mere variety 

 oiA. anceps, Eeinecke, of the Middle Oolites. I have not been able 

 to compare it with a specimen of its size, or a figure of a young shell 

 of that species ; it difiers from A. anceps in the more compressed 

 form, and in the ribs ending on the back in tubercles. The species 

 bears much resemblance to A. Hooheri, Blanford, of the Jurassic 

 beds of Niti, India. 



Log. With Alaria coronata in a greenish-grey sandy limestone 

 on the Sunday's Eiver. 



Hamites Afeicanus, sp. nov. PI. YII. figs. 5 a-5 d. 



Shell presenting an elliptical section, slightly compressed at the 

 sides; the undulating, oblique, encircling ribs are acute, very regular, 

 and separated by deep furrows. 



The five fragments in the Collection vary much in size, and con- 

 sequently in the direction of their annular foldings. In the largest 

 portion, which measures 1*7 inch in circumference, the uninter- 

 rupted rib has a slight curvature on the ventral surface, rises with a 

 gentle sweep, at an angle of 70°, to the back, forming there a slight 

 tubercle, a little without the mesial line. In portions of less dia- 

 meter, the ribs are not so oblique and acute. 



Ohs. — This species has the lobes of its chamber-partitions ap- 

 parently as in Hamites, and not as in Ancyloceras ; but the cha- 

 racter afforded by the septal lines is not always reliable, and the 

 differences between these genera are of a doubtful nature; and 

 though I refer the African form to the more characteristically Creta- 

 ceous genus, yet I attach very little value to its presence as indica- 

 tive of Cretaceous age, unless it be supported by more restricted 

 genera. 



Loc. In a greenish-grey sandy limestone at Prince Alfred's Eest, 

 and in a greenish sandy limestone at Sunday's Biver Mouth 

 (Rubidge). Dr. W. G. Atherstone, of Graham's Town, who has also 

 sent a specimen of this Hamite to England, says (in a letter, dated 



