THE CARBONIFEROUS LIMESTONE OF BURRINGTON COMBE 27 
Comparison with the Bristol Area. 
The general faunal assemblage agrees almost exactly 
with that in the same zone of the Bristol development. 
The enumeration of the resemblances would therefore 
amount to a repetition of the greater part of the above lists, 
and I shall consequently only discuss the more important 
points of difference. 
As is explained above, Horizon /3 cannot be distin- 
guished at Burrington, owing to the failure to find 
Zaphrentis and Spiriferina octoplicata occurring together.^ 
In the Bristol Area this horizon is very well marked. 
The further division of the zone into (i) Clathratus sub- 
zone, (ii) Besupinata sub-zone, (iii) Horizon y, which is 
so well established for the Bristol Area, agrees well with 
the change of the main faunal assemblage at Burrington. 
The following points of difference between the ranges 
and abundance of certain forms, at Burrington and in the 
Bristol Area respectively, should, however, be noted : — 
(i) Clathratus sub-zone. 
At Burrington — 
Michelinia occurs at the base of the sub-zone. 
In the Bristol Area — 
Michelinia has not been recorded below the resu- 
pinata sub-zone. 
(ii) Resupinata sub-zone. 
At Burrington — 
Michelinia attains a maximum and is common 
throughout. 
Amplexus is abundant in the middle of the sub-zone 
and reaches a maximum at this level. 
1 It has, however, been pointed out that the failure to recognize 
Horizon ^ at Burrington may be due to the absence of satisfactory 
exposures at this level. 
