4i56 JUEASsic CHEOisroLOGY. [vol. Ixxviii, 



were still in progress, might very well show such anomalies as the 

 Author described. He found it difficult to believe, however, that 

 the beautifully preserved annnonite exhibited, with similar matrix 

 within its body-chamber and around it, could be a derived fossil. 

 He enquired whether the hifrons ammonites which appeared in 

 inverted sequence in this new junction -bed showed the same pink 

 colour as that which characterized their matrix in the well-known 

 Junction -Bed. 



Dr. W. D. Lang asked whether a simpler explanation than that 

 suggested by the Author might not be applicable to the inverted 

 sequence ot ammonites in the Junction-Bed at Eype, namely, 

 a long period of very slow deposition coinciding with an oscillation, 

 of surface at about sea-level, allowing wave-action to mingle the 

 fossils of successive faunas, and even to remove a certain amount^ 

 of sediment; the whole deposit being subsequently consolidated by 

 a segregation of calcium carbonate. If the last-mentioned process 

 took place, it would be unnecessary to consider, as the Author 

 apparently did, that the Junction-Bed was a deep-water deposit.. 

 That such segregation would not necessarily do away with the 

 bedding-planes could be seen in the concretions of the hircld 

 nodular dej^osit, occurring in the Lower Lias of the same district.. 

 Bedding w^as very apparent in these nodules. 



Prof. P. Gr. H. BoswELL said that, among the many interesting 

 questions raised by the Author, that of the evidence of shallowing 

 conditions and instability in the area during the period covered 

 by the hemera^ from lilli to opalinifoo^mis deserved emphasis. 

 The sand}^ facies which stretched from the Cotteswolds to the 

 Dorset coast, and included the uppermost zones of the Lias and 

 lowermost zones of the Inferior Oolite, Avas characterized through- 

 out by the constancy of its peculiar lithological and petrographical 

 characters. As the Author had proved many years ago, this sandy 

 and silty jDhase transgressed as a wave of shallowing conditions to 

 successively higher horizons as the observer travelled southwards,, 

 thus providing an admirable example of the transgression of time- 

 planes by lithological planes, 



Mr. Gr. W. Lamplugh thought it improbable, on the evidence 

 adduced, that the comparatively large and well-preserved ammonites 

 found in the narrow band of fine-grained laminated material at 

 Watton Cliff: could have been derived at recurrent intervals from 

 older strata and redeposited in inverted order. Judging from the 

 specimens exhibited, he suggested that the bed might be a 'con- 

 densed ' deposit, very slowly accumulated and covering a long 

 period. In such beds the rare accident of preservation at intervals. 

 was likely to bring about the juxtaposition of forms not truly 

 contemporaneous. The further accident of collecting-chances in^ 

 beds of this kind rendered the basis for the hypothesis still narrower. 



The Atjthoe, in reply, said that the Watton -Cliff bed presented a 

 mass of puzzles, and the point raised by Dr. Davies — the difficulty 

 of derivation in the case of well-preserved fossils- — was a problem 

 already noted, not only for this instance. The solution in some 



