28 BRITISH AVONIAN CONODONT FAUNAS 
is usually developed in two beds with a parting of calcareous shale which has an 
abundant fauna. 
The Three Yard Limestone, which is eight feet thick, is a crinoidal fine grained 
limestone. 
Walker (1964 : 210) suggested that since a continuously exposed section through 
the whole Yoredale Formation did not exist in the type area, two sections, one 
representing the upper part and the other the lower part of the Formation, should be 
taken as type sections. Although Walker’s section exposes the beds of his redefined 
Yoredale Series, it does not include the lower beds of the Yoredale Formation (as 
defined by Moore 1958). Walker described the upper part of the Formation, from 
the base of the Hardraw Scar Limestone to the top of the Underset Limestone, as 
exposed in Long Sike and North Scar Gill at the head of Snaizeholme Valley 
(SD/815840) which is west of the town of Hawes. The lower part of the Formation, 
from the base of the Hawes Limestone to the base of the Hardraw Scar Limestone, 
outcrops 34 miles towards the north east in Gayle Beck (SD/864883), which is near the 
town of Hawes. The Hardraw Scar Limestone, according to Walker, forms a topo- 
graphic feature, which can be traced from the base of the first section to the top of the 
second, and this establishes the relative stratigraphic position of the two sections. 
In order to apply the conodont zonation established in south west England to 
northern England, fifteen samples, one or more being taken from each of the main 
limestones at the above localities, were processed. 
laces: 00 
GUNNERSIDE 
anl*e gd 
ale 
380 399 499 a" 
Fic. 8. Outline map of the Wensleydale area, North Yorkshire, from which the Yoredale 
succession was collected. 
