310 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 22, 



any similar stratum, or with a like series of fossils, between the Trias 

 and the Avicida-cojitorta series, or forming a part thereof. 



(2.) That the Sutton Stone is a part of the Lower Lias, to which 

 it was referred by Sir H. De la Beche. 



(3.) That the fossils of the Sutton Stone are those of the Hettan- 

 gian fauna. 



(4.) That as the Sutton Stone and the Southerndown beds cannot 

 be clearly referred by their organic remains, the one to the zone of 

 Ammonites piano rhis, the other to that of ^. angidatus, it would be 

 preferable to regard the two as tlie equivalents of the beds interme- 

 diate between the White Lias and the Bucklandi-beds. 



(5.) That the Sutton Stone presents in many particulars a close 

 analogy to certain beds erroneously called White Lias in the Bristol 

 district. 



IV. LiAssic Beds ineerioe to the Limestones oe the Ammonites- 

 Buce:landi Zone in the Bristol District. 



In the neighbourhood of Bristol two well-marked horizons are 

 known. These are the blue limestones of the " Bucklandi- series " 

 and the " Gotham Marble " (the upper limit of the White Lias). 

 It is true that the shaly beds containing Avicida cijgnipes and 

 Ostrea liassica at Horfield, which immediately underlie the Lima- 

 beds, are referred to the zone of Ammonites planorhis; but I suspect 

 that certain grey and greyish -white arenaceous limestones below 

 these shales have been erroneously regarded as belonging to the 

 White Lias ; and as they very closely approximate to the Sutton- 

 stone series, it would be well to define their characters. 



There appears to be no development of the zone of Ammonites 

 angidatus in contra-distinction from that oi A. pJanorhis in the neigh- 

 bourhood of Bristol; but the Hettangian group is represented litho- 

 logically by whitish and greyish limestones and shales containing 

 a larger assemblage of species, the majority of which more especially 

 belong to the zone of A. angidatus, than has hitherto been recorded 

 from the zone of A. jolanorhis of this country. These species enable 

 one very readily to define the base of the Lower Lias and the top of 

 the White Lias. This zone is exposed at Gotham, Wall's Gourt, 

 Whitchurch, Pyle Hill, and Bedminster, at which last locality the 

 limestones which overlie the bed with Naiadites acuminatus closely re- 

 semble lithologically those of the Sutton series, and, moreover, contain 

 one of the characteristic fossils {Lima Terquemi) of that deposit. 



The species of the following list, with the exception of Plioladomya 

 prima, collected by myself at Wall's Gourt, have been obtained by 

 Mr. G. 0. Groom-Kapier, P.G.S., at Gotham, Bristol. The determi- 

 nations are mine. 



Ammonites Johnstoni, A. planorhis ; Astarte consohrina ; Lima 

 eocaltata, L. Hettangiensis, L. gigantea, L. punctata, L. succincta, L. 

 tuherculata; Lucina cardioides ; Ostrea irregularis ; Terquemia arietis; 

 Pecten calvus, 2 species undetermined ; Perna infraliasina ; Pinna 

 semistriata ; Pholadomya glabra, P. prima ; Terehratula perforata ; 

 Gidaris Edwardsi. 



