The Invertebrate Fauna of the Uitenhage Series. 27 



pticata, was later also recognised by Dames to be a representative 

 of the genus Ptychomya,* and this seemed to point to a later age for 

 the strata from which it was obtained than that assigned by Tate. 

 Dames was further led to the belief in the Neocomian age of the 

 Uitenhage beds by a fragment of an ammonite (sent by Krauss to 

 L. von Buch) which he thought to be identical with Ammonites 

 astierianus d'Orb. 



In the concluding chapter of his monograph on the British Fossil 

 Trigonia, Lycettf referred briefly to the Trigonia of the Uitenhage 

 Formation, and expressed his opinion that some of the most 

 characteristic of these point decisively to a Cretaceous age ; he 

 also showed that the alleged occurrence of T. goldfussi, which Tate 

 had used as evidence for a Jurassic age, rested on an erroneous 

 determination. 



The whole question of the age of this fauna was afterwards well 

 handled by Neumayr,;]: who subjected Tate's work to some criticism. 

 Neumayr set on one side many molluscan types as of little signifi- 

 cance in a comparative study, and concluded that a costate Trigonia 

 (T. tatei Neum.) alone exhibited a marked Jurassic character. On 

 the other hand, he considered a number of forms to represent 

 essentially Cretaceous types. Such were Holcostephanus atherstoni 

 (Sharpe) ; Holcostephanus baini (Sharpe) ; Crioceras spinosissimum 

 (Hausm.) Neumayr ; Trigonia ventricosa (Krauss) ; Trigonia cono- 

 cardiiformis (Krauss) ; Ptychomya complicata (Tate) ; and Exogyra 

 imbricata Krauss. He suggested that Tate's Ammonites subanceps, 

 which was thought by Tate to resemble the Jurassic A. anceps Bern., 

 might really represent the young of Crioceras spinosissimum. It 

 was admitted by Neumayr that Bdemnites africanus Tate, which 

 Tate placed in the group Canaliculati and considered to afford 

 strong evidence for an Oolitic age, bears a strong res-emblance to 

 the Jurassic forms B. canaiiculatus Schloth. and B. magnificus 

 d'Orb. ; but at the same time he drew attention to the existence of 

 a belemnite in the Lower Cretaceous of North Germany which 

 seemed to share some of the characteristics of B. africanus. In a 

 later paper, written after an examination of Tate's original specimen 

 in the collection of the Geological Society, Neumayr || definitely 

 separated B. africanus from the Canaliculati, and included it in his 

 group of the Absoluti, which, as he remarked, extend in their 

 occurrence up to the Aptian ; hence the conclusive nature of the 



* Dames (1). t Lycett (3), p. 230 (1879). 



} Holub and Neumayr (1). Misquoted " implicata " by Neumayr. 



|| Neumayr (4). 



