102 



MB. S. S. BTJCKMAN ON 



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IX. 



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XI. 



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XII. 



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XIII. 



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XIV. 



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XV. 



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XVI. 



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XVIII. 



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XIX. 



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XX. 



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2_ 





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XXI. 



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XXIII. 



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Levi, — . ' Fossili degli Strati a Terebratida aspasia, &c.' Boll. Soc. 



Geol. Ital. vol. xv (1896) pp. 262-76. 

 Lang, VV. U. 'Geology of Charmouth ' Proc. Geol. Assoc, vol. xxv 



(1914) pp. 293-366. 

 Do. Discussion. Q. J. G. S. vol. lxxiii (1917-18) pp. 325-26. 

 Moxon, C. ' Illustrations of Characteristic Fossils of the British 



Strata ' 1841. 

 Oeling, M. ' Correlation of the Upper & Middle Oolites ' Proc. 



Yorks. Geol. Soc. vol. xix (1918) pp. 272-88. 

 Oppel, A. ' Die Juraformation ' 1856-1858. 

 Pojipecej, J. F. ' Beitrage zii einer Revision der Ammoniten des 



Schwabischen Jura' vol. i, 1894. 

 Quenstedt, F. A. ' Der Jura,' 1856-58. 

 Do. ' Ammoniten des Schwabischen Jura' 1883-88. 

 Rau, K. ' Brachiopoden des Mittleren Lias Schwabens ' 1905. 

 Reynes, P. 0. M. ' Monographie des Ammonites' 1879. 

 Richardson, L. 'The Geology of the Cheltenham-Stratford-on-Avou 



Railway — The Lias at the Gas- Works, Gloucester' Trans. Woolhope 



Nat. F. C. vol. for 1914-1917 (1918) pp. 137-58 & pis. i-iii. 

 Spath, L. F. ' Notes on Ammonites ' Geol. Mag. 1919, pp. 27-35, 



65-71, 115-22, 170-77, & 220-25. 

 Thompson, B. 'The Middle Lias of Northamptonshire' 1888. 

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(1899) pp.' 65-88. 

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1910, pp. 450-87. 

 Teuejian, A. E. 'The Evolution of the Liparoceratidse ' Q. J.G. S. 



vol. lxxiv (1918-19) pp. 247-98. 

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101-111. 

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(Estlichen Alpen ' Pal. (Est.-Ung. vol. iv (1886) pp. 135-226. 

 Weight, T. 'Ammonites of the Lias Formation ' Proc. Cotteswold 



Nat. F. C. vol. iii, 1864. 



Discussion. 



The President (Mr. G. W. Lamplugh) in conveying the thanks 

 of the Fellows to the absent Author, and also to Dr. Lang for 

 reading the paper, remarked that in some eases the size of the 

 fossils in a deposit appeared to have been dependent upon the 

 accident of preservation, the smaller forms having been quiekl} T 

 entombed and protected while the larger forms were partly or 

 wholly destroyed through longer exposure. The accident of pre- 

 servation was a factor of prime consequence in every discussion 

 of this kind, and, although always readily acknowledged in the 

 abstract, was liable to be overlooked in the concrete. 



Dr. W. D. Lang said that, while appreciating the great value 

 of the Author's conclusions to workers in the Lias, he was not 

 convinced of the reality of alternating periods of time characterized 

 respectively by large and by small ammonites. If this were so, 

 we should not find large and small forms in the same bed. For 

 instance, in the Belemnite Stone, very large Lytocerata were found ; 

 but there also occurred small species of Beaniceras which, no doubt, 

 the Author would call phaulomorphs. Further, he was not pre- 

 pared to go as far as the Author in recognizing non-sequences. 

 To take one instance — the Author, in his previous paper had pro- 

 posed this sequence of horizons, from below upwards — latcecosta, 



[October 30th, 1920.1 



