210 MR. G. "W. LAMPLTJGH ON THE SPEETON SERIES [May 1 896, 



clypeiform species usually recorded as Ammonites clypeiformis, 

 d'Orb., 1 examples of which under this name are preserved in most of 

 our public collections of Lincolnshire fossils ; but I do not think that 

 this determination can be sustained. It is only in its adult stages 

 that the ammonite assumes its sharply-keeled discoidal form and 

 smooth sides, since the inner whorls present a rounded back and a 

 few continuous ribs, the fossil at this stage being very near to, if 

 not identical with, Ammonites Carteroni, d'Orb. It is possible that 

 the young forms of this ammonite may occur at Speeton, but I have 

 not seen an adult specimen there. 



Among the other and more abundant fossils are Pecten (several 

 species), Exogyra sinuata (the Tealby Clay form), Ostrea from, 

 Park, (plentiful here, but very rare at Speeton), Lima, Plioladomya, 

 and many other lamellibranchs, with some brachiopods, etc. Several 

 of the above occur at the equivalent horizon at Speeton, but their 

 relative abundance in the two areas is very different. 



Pecten cinctus is often very plentiful and of large dimensions, 

 but I think that it displays characters of varietal, or even of specific 

 value, differentiating it from the similar fossil of the Claxby 

 Ironstone and Spilsby Sandstone. In the last-mentioned stratum 

 the dwarfed representatives of the species can scarcely be distin- 

 guished from P. lamellosus, Sow., of the Portlandian, and when the 

 fossil is studied throughout its extended range it will probably 

 furnish the palaeontologist with another illustration of a slowly- 

 changing species, with all the usual difficulties, to which I suppose 

 that he will in time become accustomed. Under present conditions 

 the species is, as I pointed out in my former paper, of very little value 

 as a zonal fossil. 



The evidence of the fauna, then, suffices to enable us to recognize 

 in the Tealby Limestone, as developed in the above-mentioned area, 

 some portion of the ' Zone of Bel. brunsvicensis ' (B) of the Speeton 

 section ; and the presence in Yorkshire in the clays of this horizon 

 of a considerable amount of calcareous matter, which takes the form 

 of bands of thickly- set septarian nodules of large size (' Cement 

 Beds' of Judd), indicates that the deposition of more or less 

 calcareous sediment was common to both districts at this stage. 



The evidence is insufficient to demonstrate exactly how much of 

 this extensive zone is represented by the Tealby Limestone, but it 

 seems probable that if we could have complete sections we should 

 find Belemnites brunsvicensis extending slightly below the base of 

 the limestone in most localities, and also stretching upward at 

 least as far as the lowest part of the Carstone. 



Begarding the ' Boach Ironstone and Clay ' which underlie the 

 Carstone farther south, and are by the Geological Survey considered 

 to be the southerly equivalents of the Tealby Limestone, I have no' 

 new information whatever to bring forward. Such scanty exposures 

 of these deposits as I could find were uufossiliferous, and therefore 

 practically useless for my purpose. 



1 J. W. Judd, Quart. Journ. Geol. Soc. vol. xsiv. (1868) p. 246 ; list repro- 

 duced in Geol. Surv. Mem. 1888, ' Country around Lincoln,' p. 103. 



