FROM THE ZONE OP AMMONITES ANGULATUS. 



37 



The septa are exsert, and the larger have very large dentations or papillae on them. 

 The papillae are small at the margin and at the columellary space, but midway there are 

 six or more of them which are very prominent. There are twenty-four septa, which reach 

 the margin of the columellary space, and they are strongly papillated. Between two of 

 the longest septa there are three others, one, the central, is longer than the others, 

 which are almost rudimentary ; all are papillate. There are thus five complete cycles 

 of septa, in six systems. 



The columellary space presents several small papillae, but they are septal. There is 

 no columella. 



Diameter of calice, jSths inch. Height of corallura, ^ths inch. 



Locality. jMarton, near Gainsborough ; east shore of Island Magee, in the North of 

 Ireland. In the Collections of F. M. Burton, Esq., F.G.S., Gainsborough, and R. Tate, Esq., 

 E.G.S. 



3. MoNTLiVALTiA PAPiLLATA (sp. nov.). A variety. PI. X, figs. 19 — 21. 



The corallum is smaller than the type, and the papillae are smaller and sharper. 

 Locality. Marton, near Gainsborough, In the Collection of Rev. B. Chamberlin, E.G.S. 



4. Septastrjia Fromenteli, Terqueni et Piette. PI. XI, fig. 5. 



The corallum is massive, and resembles a flattened cone in shape. 

 The corallite walls are very thin, and are fused together. 

 The calices are polygonal, irregular in shape, and deep. 



The septa are thin, finely dentate, and rather wavy; they number from twenty-four 

 to twenty-six in small calices, and from fifty-two to sixty-two in the larger. 



The fissiparous division of the calices is very constant, and occurs both in the midst 

 of the calices and at their angles. It is very rare to observe calices which do not present 

 evidences of fissiparity, so that the calices are almost always double. 



Diameter of the calices, about ^rd to jrds inch. 



Locality. j\larton, near Gainsborough ; Harbury, Warwick ; east shore of Island 

 Magee, North of Ireland. In the Collections of F. M. Burton, Esq., F.G.S., and Ralph 

 Tate, Esq., E.G.S. 



The shape of the corallum is subject to variation, and the Marton specimens are massive 

 and flat, whilst that from Harbury, belonging to Rev. P. B. Brodie, is very gibbous and 

 irregular in shape. The specimens from the North of Ireland are also irregular in shape. 

 The species has a considerable range, and it has been found by MM. Terquem et Piette^ in 

 the " Calcaire a A. planorbis de Volfsmuhl, pres de Mondorf et de Beaufort." But in 



^ Terquem et Piette, op. cit., p. 129. 



