50 RELATIONS TO OTHER BRITISH DEPOSITS. 



Myacites recurva, Phill. Ostrea dilatata, Sby. 

 Astarte or Cyprina (same as at ,, deltoidea, Sby. 



Upware). Glyphea. 



Cardium dissimile, Sby. Cidaris jlorigemma, Phill. 



Pema mytdoides, Lam. 1 Pentacrinus. 



Trigonia incuvra, Sby. Isastrcea oblonga, Flem. 



Thracia depressa, Sby. Thamnastrcea arachnoides, Park. 

 Pholadomya. 



These are found in a condition just similar to the derived fossils 

 of the Cambridgeshire and Bedfordshire Neocomian areas. 



Turning now to the native species for more positive evidence, 

 we find the result is in perfect harmony with our other con- 

 clusions. 



Of our Upware and Brickhill species 45 (a very large propor- 

 tion) are known to occur also in the Farringdon gravels. These 

 consist of 12 Lamellibranchiates, 16 Brachiopods, 4 Polyzoa, 

 3 Echinodermata, 2 worms and 6 (or more) sponges, and they in- 

 clude a number of forms of very limited range, which are of par- 

 ticular value in detailed and exact comparisons, such as Xeithea 

 omithopus, Kpng.; Opis Neocomiensis, d'Orb.; Lima Far ring donen- 

 sis, Sharpe; Terebratella Menardi, Lam. ; Terebratula prodonga, 

 Sby. and T. microtema, Walker. 



The identity of the Sponges and Polyzoa of Upware and Far- 

 ringdon is also very striking, all the more common Upware species 

 being of frequent occurrence at Farringdon likewise. 



Still there are some prominent differences which give to each 

 of these two faunas a well-marked character of its own when con- 

 trasted with one another. This is apparent in a glance at any 

 collection from the two places : but much even of this apparent 

 isolation in the characters of the Upware and Farringdon fades was 

 broken down with the discovery of the new fossil area at Little 

 Brickhill near Bletchley. This little village lies just about mid- 

 way between Upware and Farringdon, and it was extremely 

 pleasing to find that its Lower Greensand fauna was likewise 

 of just a corresponding intermediate character. Its close con- 

 nexion with the Upware bed we have already seen, supra, p. 47, 

 and its affinity to the Farringdon sponge bed is especially manifest 

 in the abundance of Peltastes Wrightii, and the presence of Lima 

 Famngdonensis, Terebratella Menardi, T. oblonga, and Terebratula 

 Tornasensis ; also in its Polyzoa and Sponges. 



