A84 Geoloyical Society. 
to Spiviferina include two types characterized by external diffe- 
rences. Of these two types, one, in which there are numerous 
ribs and a relatively-large rounded fold and sinus, is relegated to a 
new genus; while the members of the other type, which include 
shells with a few large angular ribs, are for the present retained in 
Spiriferina, although the type-species of that genus was derived 
from the Lias. The subdivision here suggested for the Carbonifercus 
forms will, it is believed, prove to be applicable to the later species 
also. 
2. ‘Jurassic Chronology: I—Lias. Supplement 1, West 
England Strata.’ By S. S. Buckman, F.G.S. (Read, in the 
absence of the Author, by Dr. W. D. Lang, M.A., F.G.S.) 
In this communication the following points are discussed :— 
(1) The Ammonite and some Brachiopod 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 be considered :—Stratal, 
Depositional, Faunal, Dispersal, Exposure, Collection, Arrangement, 
Nomenclature, Fossilization, Preservation, Extraction, Zonalization, 
Publication; but several of these are not applicable to results 
derived from the investigation of hmited areas. 
(4) The evidence appears not only to support the conclusions of 
the Author’s 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 Schlotheimie 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 
Liassie 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 
further subdivisions in the scheme set forth in the Author’s former 
paper. 
