pArt 4] JUEASSIC CHEONOLOGY. 391 



are on the same horizon as his Saurian Bed, which seems likel}^ 

 but is not yet definitely proved. From Moore's evidence it may 

 be judged that the Rhynclionella-houcharcU Zone is ^ve-falci- 

 feritm ; but how much earher? Was it ])YQ-exaratum'^ Its 

 absence from Yorkshire and the failure of exaratum-Vike ammo- 

 nites from the South- West of England, where JRJu/nclioneIJa 

 houcliarcU is not unusual, seem to indicate that it is not actually 

 of exaratum date. 



III. Succession in the Upper Lias of Stroud, Gloucestershire 

 (according to E. Witchell).^ 



\bifrons- [^Ammonites] hifrons, A. serpentinus {^Harpoceras falciferuin 



falcifentm. et aff.], A. communis [Dactylioceras spp.]. Fish-remains 



rare. 



glohulina.'] Terehratula glohulina and Rhynchonella pygmaea in consider- 



able numbers. 



IV. Succession in the Upper Lias of Churchdown, Gloucestershire 



(according to F. Smithe, cited by E. Witchell).^ 



'Crustacean' [Bed]. 

 [mwieyi. ' Fish-Bed.' 



'Alga-Bed.' 

 Leptsena. ' Leptsena Bed.' 



glohulina.'] ' Terehratula glohvlina ' [Bed]. 



V. Succession in the Upper Lias at Alderton (Dumbleton), sum- 



marized from various authorities'^ and from personal observations. 



\^hifrons- 3. Shales with Hildoceras, Harpoceras, Dactylioceras, 



falciferum. 44 feet. 



innrleyi. 2. Saurian, Fish- and Insect-Bed: Light-ochre Fissile Bed; 



Ammonites murleyi,'^ 1 foot. 

 glohulina.] 1. Paper-shales, ^Leptsena Shales,' Terehratula glohulina, 



Rhynchonella pygmasa, 15 feet. 



This is the northernmost point, I think, at which the small 

 Terehratula and Hhynclionella have been observed ; but their 

 range is wide, as it extends into Normandy. Therefore they are 

 good for dating. It is doubtful whether Lepfceiia has been found 

 at Alderton (Dumbleton). IMoore mentioned the Leptcena Clays 

 as 15 feet thick there ; but he may have recognized them only by 

 the presence of the Terehratula and JRliynclionella. H. B. Wood- 

 ward's citation of Leptcena from these clays may have no other 

 basis than Moore's remark. I have collected the Terehratula 

 and HJiynclionella, but have seen no other brachiopods tliere, and 

 Mr. Linsdall Kichardson mentions the two former, though he does 

 not cite LeptcBua.^ Witchell's evidence from Stroud is to the 

 same effect. 



' XIII, p. 25. 2 XIII, p. 26. 



•■* VII, p. 149 ; IX, p. 56 ; X, 1, p. 36 ; XIV, p. 267. 



' The following species of ' Ammonites murleyi ' have now been published. 

 Murleyiceras m^uieyi (I, 8, ccxvi), M. forte (ccxlv), M. aptum (cccxvi). 

 '> IX, 1, p. 57. 



