The Invertebrate Fauna of the Uitenhage Series. 45 



value of Trigonia mamillata as an indication for age has already been 

 considered, and the supposition of the Cretaceous rather than the 

 Jurassic affinities of this form receives emphatic support from the 

 presence of Trigonia ventricosa and T. pulchra, both members of the 

 section Scabrse. Though claiming corroboration of his views from 

 Trigoma which he supposed to be related to Portlandian forms, 

 Waagen did not state that these were found in actual association 

 with his Oornia ammonites ; and the fact that none of the critical 

 ammonite-species upon which he relied in his correlation is recorded 

 from any of the localities such as Goonaree, Oomia, or Huroora, 

 where the Trigonia-beda are well developed, gives room for the 

 suggestion that the ammonites and lamellibranchs may not represent 

 horizons of quite the same geological age. Further, if we examine 

 Waagen's descriptions and figures of the four ammonites which were 

 thought to represent European forms, it may perhaps be allowed 

 that too much reliance has been placed on the evidence they were 

 supposed to afford. Two were referred only with doubt to the 

 respective European species; of the remainder, one represents a 

 type of Perisphinctes which, so far as can be judged from the 

 description and figure, does not justify the definite conclusions drawn 

 by Waagen concerning its relation to a European Portlandian form. 

 The other, a single specimen referred to the Tithonian Perisphinctes 

 eudichotomus Zittel, is so preserved that the lobe-line is not visible, 

 and a comparison of Waagen's figure with Zittel's original specimen 

 in the Palaeontological Collection of the State at Munich shows that 

 the Indian form is rather thicker and more involute, though the 

 agreement is otherwise good. 



It is scarcely necessary to dwell at any length on the question of 

 the alleged discrepancy between the evidence of the plant and animal 

 remains in settling the age of the Oomia beds, since this matter has 

 already been so fully dealt with. The plants of the Oomia group 

 were obtained from strata for the most part above the marine beds 

 which yielded the cephalopods and lamellibranchs, but they led 

 Feistmantel to refer these beds to the Middle Jurassic. Even should 

 a revision of the Oomia plants prove the correctness of Feistmantel' s 

 view that the flora exhibits Oolitic affinities, there are many reasons 

 why the evidence of the marine fauna must be allowed to outweigh 

 that of the plants in a correlation with European stratigraphical 

 standards/ 1 ' 



Putting on one side the ammonites, the exact bearings of which 

 on this question are somewhat doubtful, it may be said that there is 

 * W. T. Blanford (2). 



