INTRODUCTION. 25 



to be numerous as a class or particularly well preserved, many appearing in the 

 condition of casts. The " Oolite Marl " yields a fairly respectable list of Gastero- 

 poda, and some of these are really in good condition, well preserved in fine white 

 calcite, so as to constitute a valuable acquisition to the cabinet. Mr. Brodie also 

 has some good specimens of Gasteropoda, mostly small, from the freestones, which 

 bear some resemblance to the Fauna and facies of the Lincolnshire Limestone. 

 On the whole, however, the Cotteswold area of the Inferior Oolite is rather dis- 

 appointing, and if it were not for the abundance of Nerinaa on certain lines 

 in the " Oolite Marl " and associated beds, and the occurrence of this 

 genus to a less extent in the " Pea-grit " below and the " Clypeus-grit " 

 above, the ground would be somewhat poor hunting for those in search of Gas- 

 teropods. It has generally been held, and I thiuk justly, that these shells are in 

 some way associated with coral growth, and this seems all the more probable when 

 we bear in mind that the No. 1, or Dorset district, notwithstanding its wealth of 

 Gasteropods, has not yielded a single Nerinaa to collectors, so far as my experience 

 goes. The genus Nerinaa lias been traced as far as Radstock in the uppermost 

 beds of the Inferior Oolite, but south of the Mendips it seems to be entirely absent, 

 and this is also the case with beds on the same horizon in Normandy. 



In the East Midland district, if we except the development of certain estuarine 

 and ferruginous deposits, the Inferior Oolite is still mainly calcareous. The 

 Lincolnshire Limestone is remarkably devoid of Cephalopoda, and the facies, where 

 any abundance of fossils occurs, is described by Professor Judd as partly coralline 

 and partly shelly. With few exceptions the Gasteropoda are small, but excessively 

 numerous in certain places, and the genus Nerinaa is well represented throughout. 

 It would be difficult to show a greater contrast than that which exists between the 

 Lincolnshire Limestone, with its white Oolite, small shells, and total absence of 

 Ammonites, and the Dorsetshire ironshot Oolites, so full of Ammonites and 

 Belemnites that Mr. H. B. Woodward declares the entire Inferior Oolite of that 

 region might be called a Cephalopoda-bed. 1 It is probable that the greater part of 

 the Lincolnshire Limestone belongs to the Lower Division, though matters are more 

 obscure here than in the south-west. The facies and general appearance of the 

 upper beds of the Lincolnshire Limestone at Weldon, Wansford, Barnack, &c, has 

 a strong resemblance to the Great Oolite as developed at Minchinhampton and 

 elsewhere, but possibly this resemblance is in part superficial, and it may be that 

 the freestones of the Inferior Oolite in the Cotteswolds, on a close comparison of 

 species, may have more affinity with the Lincolnshire Limestone than is usually 

 supposed. 



1 ' Proc. Geol. Assoc.,' vol. ix, p. 203, 1886. 



