70 BRITISH FOSSIL CORALS. 



so mixed up with that of the Ainvionifes angulatus that it had better disappear from 

 liritish geology. 



Mr. Tate, however, supports indirectly the geological position I have given, from the 

 study of the Madreporaria, to the Sutton Stone and Brocastle deposits. 



I agree with Mr. Bristow, or rather he agrees with me, as I was first in the field, that 

 the Sutton Stone is what is usually called Lower Lias ■} but I dispute the possibility of 

 associating the Sutton Stone, Brocastle, and other equivalent deposits, including, of 

 course, the Coral-bed of Cowbridge, with the strata composing the Ammonites BucMandi 

 Zone in the same division of a great formation. 



The word " Infra-Lias, " which refers to the deposits below the Ammonites BucJdandi 

 series, does not assume separation from the Lias, and, although Low, Lower, and Lowest 

 will apply to some places, it would rather confuse a geological series. 



To combine in one division of the Lias, under the term Lower, such zones as those of 

 Ammonites raricostatus and Ammonites planorbis is to associate widely different faunae. 

 There are many species which have a great range in this division of the Lias, but there is 

 a clear palseontological distinction to be drawn in the British Isles, in France, Luxem- 

 bourg, and in Germany, between the faunae of the Zone of Ammonites Buckkmdi and of 

 those below. 



Ostrea irregularis {0. Liassica) is a shell so widely distributed, and has so great a 

 vertical range, that it is of no value in fixing a geological horizon. It must be considered 

 in relaton to the fauna associated with it ; and the forms found in the Sutton Stone in 

 company with this variable Oyster are not those which elsewhere characterise the Ostrea 

 beds of the A. planorbis Zone. 



I have examined the Gryplicece, and do not consider them typical incurvm. The cha- 

 racters of the Molluscan and Madreporarian fauna which I have already pointed out, and 

 the affinities and grouping of the species, induce me to retain my opinion that the Sutton 

 Stone, the Brocastle, Ewenny, and Cowbridge deposits are on one geological horizon, and 

 still to assert that they are the equivalents of the French and Luxembourgian Zones of 

 Ammonites angidatus. 



The deposits have a different Coral-fauna to the corresponding beds in the east of 

 England, where simple Montlwaltice indicate different external conditions, but not a 

 difference in time. 



Corals from the Upper Lias. 



MM. Milne-Edwards and Jules Ilaime described Thecocyathus Moorei, Ed. and H., 

 from tlie Upper Lias of Ilminster. Mr. Charles Moore has sent me specimens from Lans- 

 down, near Bath. The same excellent collector has a fossil, probably a Sponge, with 



' Sir Henry de la Beche was the first to prouounce the Sutton Stone to belong to the Lower Lias. 



