252 DE. A. E. TEUEMAN ON THE [vol. lxxiv v 



while involute forms of the henleyi and hechei series occur 

 respectively in the Liparoceras 1 and Oistoceras sub-zones of the 

 zone of Deroceras davcei. 



Around Cheltenham, beds with striatus-\ike forms are succeeded 

 by beds with capricorns, these being immediately below the Middle 

 Lias (Marlstone Series) of the district, and this has been accepted 

 as the normal sequence. The striahis-like ammonites, however, 

 are of the Liparoceras series, and are similar to those found in the 

 upper part of the ibex zone of Dorset. Since no higher horizon 

 with involute Liparoceratids has been detected in South Gloucester- 

 shire, it is extremely probable that most of the davoei zone is not 

 represented there. Further, some of the Capricorn ammonites of 

 the Cheltenham district are similar to those found in the latce- 

 costa sub-zone of Dorset, while others are of a different type, and 

 probably indicate a horizon that is not represented in Dorset. 2 



At Napton-on-the-Hill (Warwickshire), at Dumbleton, and in 

 some other parts of Gloucestershire, lower becis are present, con- 

 taining Capricorn ammonites of the Liparoceras series, of which 

 involute forms only are known in Dorset. As the Napton pit was 

 not in work at the time of my visits no thicknesses can, with any 

 certainty, be assigned to these beds. The following general suc- 

 cession was determined : — 



™rgaritatusr mMleU ^ 

 zone. |_ 



, * ■< Beds with Capricorn ammonites of the A. latxcosta group, 



sub-zone. I 



"Beds with Capricorn ammonites of another series (Beani- 



ceras). 

 Beds with involute Liparoceras (L. obtusinodum and other 

 ibex zone. -{ spp.). 



Beds with capricorns of the Liparoceras series. 

 Beds with Acanthopleuroceras valdani.. 

 Beds with Tragophylloceras ibex. 



The succession at Dumbleton is probably very similar (see- 

 Table I). At Radstock (Somerset) bituberculate sphaerocones of 

 a different type occur at a still lower horizon : namely, the valdani 

 zone, and it is therefore probable that another group of capricorns 

 will be found below this level. 



South of Lincoln the upper part of the Lower Lias is again 

 exposed, and the Oistoceras and daedal icosta sub-zones, which 

 are presumably absent in Gloucestershire and Warwickshire, are 

 represented by thin but very fossiliferous deposits. Fossils of the 

 Oistoceras sub-zone may also be found in the lowest beds of the 



1 This is an unfortunate name, since by Liparoceras were meant involute 

 ammonites of the henleyi series, which are here assigned to Androgynoceras, 

 while Liparoceras is confined to lower beds. The name dsedalicosta sub-zone 

 is here proposed to take the place of Dr. Lang's Liparoceras sub-zone. 



2 See S. S. Buckman, ' Jurassic Chronology : I. Lias ' Q. J. G. S. vol. lxxiii 

 (1917-18) p. 264. 



