WELL-SINKING AT SWINDON. 



293 



marly beds, but the exact position of the greater number is un- 

 certain ; — 



Cristellaria crepidula, F. ^ M. 



cultrata, Monff, 



rotulata, Lam. 



Lituola nautiloidea, Lam., var. 



depressa?, Jones. 

 Serpula tetragona, Sbr/. 

 Cytheridea subperforata ?, Jones. 

 Echinobrissus clunicularis, Luid. 

 Ehjnchonella varians, Schloth. 

 Waldheimia obovata, Shy. 



ornithocephala, Sby. 



Avicula echinata, Sby. 

 Lima, sp. 



Ostrea, sp. 



Pecten demissus, Phil. 

 Gresslya peregrina, Phil. 

 Modiola Sowerbyana, d'Orb. 



, sp. 



Myacites decurtatus, Phil. 



securiformis, Phil. 



sinister, Ag. 



Terquemeus, Buv. 



Trigonia, sp. (costate form). 



, sp. (clavellate form). 



Cylindrites? 

 Natica, sp. 



EoREST-MARBLE. 



The beds from 703 feet to 736 feet, the lowest depth at present 

 reached, are regarded as Forest-marble. The fossils were chiefly 

 obtained from the lowest part, about 730 feet, and in the thin clay 

 partings of the harder shelly rock. 



Wood. 



Serpula tricarinata. Shy. 



tetragona, Sby. 



, sp. 



Cidaris, spine. 



Acrosalenia, spines and plates. 

 Pentacrinus scalaris, Goldf. 

 Diastopora diluriana, Lamx. 

 Entalophora (Spiropora) straminea, 

 Phil. 



, sp. 



Terebellaria ramosissima, Lamx. 

 Rhynehonella concinna, Sby. 

 Waldheimia digona, Sby. 



Waldheimia obovata, Sby. 

 Terebratula coavetata, Park. 

 Avicula, sp. 

 Ostrea gregaria, Shy. 



(Exogyra) lingulata, "i L. ^ M. 



Sowerbyi, L. ^ M. 



Pecten vagans, Sby. 



lens, Sby. 



Lima duplicata, Sby. 

 Area, sp. 



Modiola imbricata ?, Sby. 

 Oerithium, sp. 

 Gasteropods (minute). 



E. T. N. 



3. Few fossils have been obtained from the Ejmeridge Clay, but 

 they include one Ammonite {A. corclatus)., an Oxfordian form, which 

 is known, however, from the Lower Kimeridge Clay of Yorkshire. 



Towards the base of what is now included in the Kimeridge Clay 

 at Swindon there is a bed of iron-shot earthy limestone, six inches 

 in thickness, which has yielded Ammonites corclatus.^ var. excavatus 

 (regarded as the Ammonites serratus of Sowerby), and this is a well- 

 known Lower Kimeridge fossil, though found also in the Oxford 

 Clay. A. rotundus likewise occurs, and this is a Kimeridge form*. 

 Ostrea deltoidea occurs, and this species is abundant in the upper 

 Corallian beds in many localities. 



This fossiliferous bed reminded me of the gritty limestone of 

 Ringstead Bay, near Weymouth, termed the " Kimeridge Grit " by 



* See J. F. Blake, Quart. Journ. Geol. Soc. vol. xxxi. pp. 211, 215, &c. 



