FROM NORTHWESTERN EUROPE 101 
DIMENSIONS OF FIGURED SPECIMENS. 
length thickness width 
2°97 cm 2:20 cm 3°35 cm 
2°55 cm I-95 cm 2:80 cm 
Internal characters. Most of the fine detail of the structures has been lost through 
recrystallisation. 
Pedicle valve. The narrow, elongate lateral cavities, which penetrate almost to 
to the apex of the beak, are limited by slender dental lamellae. A pedicle collar is 
present. The teeth are strong and crenulated ; lateral denticulae are present but 
not strongly developed. 
Brachial valve. There is no septalium and only a weak median septum ; small 
septalial plates are present. The sockets are crenulated ; inner and outer socket 
ridges well developed. Crural bases are not well differentiated. The radulifer 
crura are flattened in the plane of articulation and do not curve towards the pedicle 
valve. 
DIsTRIBUTION. The species only appears to have been recorded from the following 
two areas. (1) The material of Jacob & Fallot (1913) came from St. Vallier in the 
French Alpes Maritimes and in the “ Portlandien coralligéne des environs de Gerin, 
Ain”’. The latter name is probably a mis-spelling of Cerin. (2) All the material 
studied by the author was collected by various members of Imperial College from the 
southern French Jura in the area around Belley, which is also in the Départment of 
Ain. 
OCCURRENCE. The material described by the author was collected from the 
Bedded Virieu Limestone (Ager and Evamy, 1963). The following description of 
mode of occurrence and lithology is taken from Evamy (1963), ‘“‘ The subdivision 
(of the Bedded Virieu containing T. guebhardi) is about 20 m thick—it consists 
mainly of alternating limestones and shales, which yield an abundant brachiopod, 
lamellibranch fauna, as well as ammonites of the tenwilobatum and pseudomutabilis 
zones—. The limestones are thinly bedded (20-40 cm) brown calcilutites, occasion- 
ally showing a mottled iron-staining. These are separated by thin (approximately 
Io cm) shaly bands.”’ He also noted that, “A few thicker beds of calcilutite 
(1-14 m) are seen not to contain the abundant mollusc and brachiopod fauna .” 
The beds containing 7. guebhardi immediately underlie the reef horizon of the 
Massive Virieu Limestone. 
Remarks. Although the author has not seen the original material of Riyncho- 
nella Astieriana var. Guebhardi, it is thought that a conspecific identification for the 
material from the Bedded Virieu Limestone can confidently be given as it matches 
exactly the specimen figured by Jacob & Fallot (1913). Also, the Bedded Virieu 
could well be the lateral stratigraphical equivalent of the “ Portlandien ” of Jacob 
and Fallot. Referring to the Bedded Virieu, Ager and Evamy (1963) note that it 
is, ‘‘ strongly reminiscent of the ‘ Tithonien’ facies seen in many parts of Europe 
at this level ’’. In the latter publication, 7. guwebhardi is referred to as Septaliphoria 
astieriana (d’Orbigny). 
