BRITISH AVONIAN CONODONT FAUNAS 243 
denticle anteriorly to the anterior arch beneath the anterior bar, and posteriorly to 
where the posterior bar is broken. 
REMARKS. This form is unlike any other described conodont genus. 
Gen. nov. B. sp. 
Plate 25, figs. 7a, b 
MATERIAL. 1 specimen : figured, X 410. 
RANGE. Farlow ORZ 1. 
DESCRIPTION. This specimen is one of problematical affinities ; its essential 
features are that it has a conspicuous, elongated, main denticle, which is subtriangular 
in cross-section, with a more or less sharp anterior edge. Its anterior aboral margin is 
very flat, but has a narrow slit extending for a minute distance up the median part of 
the face. It is recurved posteriorly, even though there is no posterior bar. Its base 
is very thick-lipped and is regularly expanded as a relatively wide and deep cavity. 
It appears that this anterior denticle is complete, though this is not certain. On the 
outer lateral face, there is an anterior aboral process which makes an angle of about 
go° with what would be the line of the posterior bar, and it is also depressed in a 
vertical plane. Its anterior face is very convex in anterior view, and its anterior 
distal end is straight-edged, with a sharp antero-aboral corner, but this is fractured in 
the specimen. Its oral surface bears 3 denticles, of which the two innermost are 
massive, with bluntly formed lateral edges and strongly convex anterior and posterior 
faces. The denticle at the distal end is conspicuously smaller than the other two, 
and the interior denticle, although very broad at the base, divides distally to give 2 
separate denticles. There is a tendency for germ denticles to develop between the 
larger denticles. The posterior lateral face of the anterior aboral process is flat and 
the base is continuously excavated. 
RemaArRKS. The fact that this specimen appears essentially complete makes it 
impossible to assign it to any existing genus. It may, in fact, represent a new one, 
but it is possible that it is a broken specimen of Hindeodella corpulenta. 
VII. SUMMARY AND CONCLUSIONS 
(a) Scope of the present work 
During the last decade, studies in both Germany and the United States have 
demonstrated the potential value of conodonts in Carboniferous and Devonian strati- 
graphical correlation. The present study represents a comprehensive description of 
the conodont faunas of the British Lower Carboniferous, and a detailed analysis of 
their stratigraphical distribution. This has been used to erect a zonal scheme, by 
means of which a more precise correlation has been established between sections in 
each of the main British Carboniferous depositional provinces than any yet available 
on the basis of other faunal groups. Intercontinental correlations are also suggested. 
