1870.] South-west of England. 71 



The range of the 84 determined species is as follows : — 



Peculiar to the formation 2 



Common to the inferior oolite and Fuller's-Earth . . . . 33 



„ „ great oolite „ „ .... 13 



„ „ three formations 36 



Accordingly, 69 species, or 83 per cent., occur in the Inferior 

 Oolite, and 49 only, or 60 per cent., are found in the Great Oolite or 

 superior formations. These results lead us to the inevitable con- 

 clusion, that the Fuller's-Earth is a subordinate member to the 

 Inferior Oolite rather than to the Great Oolite, as hitherto con- 

 sidered. 



The Inferior Oolite presents in its organic remains at least a 

 twofold aspect, and whilst the older fauna is to some extent re- 

 peated in the Great Oolite, the newer fauna lived on during the 

 deposition of the Fuller's-Earth, but did not extend into the Great 

 Oolite. Indeed, the majority of the species common to the Fuller's- 

 Earth and the Inferior Oolite made their appearance in time in the 

 upper zones of the Inferior Oolite ; such are : — Serpula tetragona, 

 Holectypus depressus, Hyboclypus gibberulus, Glypeus Plotti, G. 

 Hugii, Echinobrissus clunicularis, Waldheimia ornithocephala, 

 Terebratula jperovalis, T. globata, Bhynchonella varians, M. spinosa, 

 Cypricardia Bathonica, Geromya Bajociana, C. striata, Goniomya 

 angidifera, Isocardia nitida, Mytilus Sowerbyanus, Ostrea acu- 

 minata, Pleuromya sequoia, Pholadomya Heraulti, Ammonites 

 ParJcinsoni, A. discus, &c, &c. 



And so close is the affinity subsisting between the fauna of the 

 zone of Ammonites ParJcinsoni and the Fuller's-Earth, that massing 

 the species of these two horizons, the contrast in their numerical 

 relations to those of the lower zones of the Inferior Oolite is as great 

 as that which they present to those of the Great Oolite. 



£In conclusion, the Fuller's-Earth is not a formation, but only 

 the uppermost, or a fourth, zone of the Inferior Oolite. Here, there 

 is a marked decadence of Inferior Oolite species, yet at the same 

 time the facies is decidedly after that fauna. 



