'392 MR. s. s. EL'CK:\rAX ox [vol. Ixxviii, 



The point is that, if the various species of LepfcBiia are absent 

 from the thick deposit of Alderton, which contains the minute 

 Terehratida and Hhi/nclioneUa. it may be because the Lepfcdua- 

 Beds are not really synchronous with the glohuUna beds, although 

 in places (Ilminster and Xormandy) the two may be mixed owing 

 to paucity of sedimentation. Smithe's record at Churchdown 

 supphes some evidence in this connexion, giving the globidina- 

 bed below Leptcsna. The data are insufficient, and further 

 research is required. But they show that, in the case of Church- 

 doAvn, records from the LeptcBna Bed and from t\\Q glohuliaa bed 

 should be kept separate, and that while the strata of Alderton 

 (Dumbleton) and Stroud are known to be of glohulina date, they 

 are not known to be of Leptciena date. The same may be the case 

 with other localities whence Leptcena Clays have been cited. 



The next piece of evidence for the separation of the LeptcBiia 

 and qlohiiUiia beds would be to find the former without the latter. 

 Moore's records of his finds at Whatley come in here : he obtained 

 three species of Leptcdua, but makes no m^ention of Terehratula 

 fflohulina nor of RliynclioneUa pycfmcea)- He gives a similar 

 result for Sandford [Orcas, Somerset]. 



Therefore the faunal analysis works out as follows : — 



XoEMAyDY. SoilEESET. GlOTJCESTEESHIRE. 



, K 



^ ^ .-^ 



Caen. Ilminster. Sandford Wbatle}'. Stroud. Church- Alderton. 



Orcas. down. 



Leptcena X X X X ... X ? 



T. glohulina ... X X ... ... XXX 



These records o-ive at least sufficient reason for a theory of two 

 deposits at two different dates. At any rate, it is necessary to 

 keep them distinct for recording purposes, and not to credit a 

 locality with the possession of the LeptcBna Beds ~ merely on the 

 evidence of the Terehratula and Ulii/nchonella. 



Similar mistakes to this we have all made in the past — a relic of 

 the old teachino;, which consistently obstructed all increase in the 

 number of names — of zones, of genera, or of species. That was a 

 wrong doctrine ; because it will now give much more trouble 

 than the other course, and impairs the value of many old records. 

 It is to be hoped that what may be called the ' analytical method ' 

 Avill be pursued in the future, even if it does involve the use of 

 many names. 



A consideration of these Upper Lias records suggests the fol- 

 lowing succession ; but it is incomplete. There are gaps (non- 



1 ni, p. 157. 



■■2 The Leptsena Beds have a wide range— the South- West of England, • 

 Xormandy. Wiirtemberg : also Sicily, according to the title of a paper by 

 G. G. Gemmellaro. ' Sugli Strati con Leptaena nel Lias Superiore di Sicilia ' 

 Boll. Com. Geol. Ital. vol. xvii (1886) pp. 156, 341. 



