258 BRITISH AVONIAN CONODONT FAUNAS 
| O syle) Te 
Z 
a eraraera 
a TST oT 6] 
O oie 
G 
G 
ie 
: 
: 
Cl 
i 
i 
\N 
S A 
A 
aa 
NJ 
te 
i 
E " 
\\ 
AN 
SH 
c 
A 
Hn 
au 
\N 
\ 
: a 
en 
an 
NWN 
Pr orb ore GY 
pr erh orn Y), 
eae YY) 
zia7vft TTT W)éJMéMJaadldédd 
ee eee ae WY, 
rea LLL 
O 10 20 30 40 50 60 70 £80 OO 5 10 15 
Abundance factor = [otal no.of specimens Total weight of sample 
Total weight of sample in kilograms 
Fic. 71. Lithological section of the Z and Sg Zones of the North Crop of the South Wales 
Coalfield showing the abundance factor of conodonts in each sample, and the total weight 
of limestone dissolved. For details of collecting localities see Fig. 7 and also p. 25. 
