4 BRITISH AVONIAN CONODONT FAUNAS 
ABSTRACT 
THE conodont faunas of the Lower Carboniferous of the South West Province, the 
Yoredales and the Midland Valley of Scotland are described. A complete series of 
samples was collected from the Avon Gorge section, Bristol, and also from composite 
sections from the North Crop of the South Wales Coalfield, the Clee Hills, Wensley- 
dale, Dunbar, Fife, Roxburgh, Midlothian, Ayrshire and Argyll. A total of over 
600 samples was collected at intervals ranging from ten feet (Avon Gorge) to six 
inches (Dunbar). The calcareous samples were dissolved in either 8° acetic acid or 
15% formic acid, and the argillaceous samples subjected to 100 vol. hydrogen 
peroxide. Some 3 tons of rock was processed. 
All collected sections are illustrated and charts of the conodont abundance (number 
of specimens per kilog.) and weight of rock dissolved, together with sample numbers, 
are presented. In all, the samples yielded over 25,000 identifiable specimens, 
referable to 167 species, belonging to 29 genera, of which 2 named genera (Clydag- 
nathus and Patrognathus), 40 species and 13 subspecies are new. All species are 
described and illustrated, and range charts of their vertical distribution are pre- 
sented. 
The faunas are divided into a total of 14 conodont assemblage zones and correla- 
tions are made between standard sections in the various Carboniferous provinces of 
Great Britain. There is a strong general similarity between the succession of 
conodont faunas in North America, Germany and Britain, although there are also 
some striking local differences. These are analysed in the light of conodont phylo- 
geny, distribution, and of possible sedimentary breaks in various sections. Correla- 
tions are made with the standard goniatite sections of Germany and with the type 
sections of the Mississippi Valley. 
Within the South West Province the basal part of the K Zone is correlated with the 
Cu I goniatite zone and the upper part with Cu II « ; the uppermost K to the Upper 
Se Subzone is correlated with the Cu II Zone, and the Dj, Dg, and D3 Subzones with 
the Cu III goniatite zone. 
The upper part of the Calciferous Sandstone Measures of the Midland Valley of 
Scotland is of Cu III « age, the Lower Limestone Group is of Cu III @—y age, and the 
Upper Limestone Group is of E;—-E2 (Namurian) age. 
I. PURPOSE AND SCOPE OF PRESENT STUDY 
Conodonts were first described in 1856, and, although they were described in only 
a few papers in the subsequent seventy-five years, there is now a total of some 1,200 
publications devoted to them. Doubt and controversy concerning their function 
and affinities remain greater now than a century ago. One recent author (Fahlbusch, 
1964 ; see also Beckmann et al., 1965) has argued that they represent algae, and 
another that they were internal supports in some ciliated tentacle apparatus of an 
unknown filter-feeding organism (Lindstrém, 1964), while still another (Foss, 1960) 
has suggested that the similarity of their carbonate fluorapatite composition to that 
of scales of the Ordovician chordate Astraspis implies an affinity between the two. 
