98 MR. S. S. BUCKMAN ON [vol. lxXVl, 



P. 276. Table IX, Wessexian 7. A cross should be put under Wiirtem- 

 berg, to indicate the presence of the bronni fauna there. 



P. 282, line 7. M». C. P. Chatwin tells me that he has now found a copy 

 of Mayer- Eymar's paper in the Society's Library, bound up in a series 

 of tracts. 



P. 292, footnote 2. For ' S. 32 ' read ' S. 16.' 



P. 293, footnote 4. For pi. xlv read pi. xlii. 



P. 316. line 11. For ' 360 ' read ' 260.' 



line 22. For ' XXX ' read ' XXXI." 



P. 324, line 15. For ' leviceras' read ' Gleviceras." 



Y. Summary. 



In this communication the following points are discussed : — 



(1) The ammonite and some hrachiopod faunas of the Lias 

 of Gloucestershire and Worcestershire. 



(2) A method of faunal plotting as an aid to faunal analysis. 



(3) That in the collection, analysis and comparison of faunas, 

 the following causes of failure have to he considered : — Strata 1, 

 Depositional, Faunal, Dispersal, Exposure, Collection, Arrange- 

 ment, Nomenclature, Fossilization, Preservation, Extraction, 

 Zonalization, Publication ; hut several of these are not applicable 

 to results derived from the investigation of limited areas. 



(4) The evidence appears not only to support the conclusions 

 of my former paper, but to show that in certain cases a fuller 

 sequence of faunal episodes may be required. 



(5) The fauna of small ammonites in these Liassic beds, 

 especially that of small Schlotheimice at Gloucester, suggests 

 comparison with the faunas of Hierlatz and Spezia. The use 

 of technical terms for different sizes of organisms, especially for 

 small forms, is briefly illustrated. 



(6) It is suggested that the strata and faunas of these Conti- 

 nental localities are not so exceptional as they appear to be at 

 first sight ; and that English localities may be studied with 

 advantage, in comparison with and explanation of the features 

 of these Continental deposits. 



(7) It is found that the preserved strata of the Gloucestershire- 

 Worcestershire Lias under consideration happen in the main to be 

 deposits of dates when the living ammonites were rather small ; 

 while there is faunal failure and presumably stratal failure of the 

 times when large ammonites flourished. The converse phenomena 

 are mainly illustrated by North- Somerset deposits. 



(8) The times when large and small ammonites lived appear to 

 follow one another like waves, illustrated even in a short table of 

 Liassic deposits. 



(9) As a result of the investigations connected with this paper 

 it seems to be advisable, for recording purposes at any rate, to 

 make the following further subdivisions in the scheme set forth 

 in my former paper : — 



