1865.] PUXCAN STJTTON-STONE COEALS. 89 



28. TUERITELLA, Sp. 



I have some small species from the Sutton Stone which may belong 

 to this genus and to Chemnitzia, but which it is impossible to recognize 

 specifically. 



29. Trochotoma, sp. 



A very flat form from the Sutton Stone may probably be referred 

 to this genus. Its imperfect state prevents a description. 



30. Natica PylensiSj spec. nov. PI. lY. fig. 10. 



Shell ovate. Body- whorl large. Spire depressed, of two volu- 

 tions. Suture deeply impressed. Apex blunt. Aperture semicir- 

 cular. Length 0*1 to 0-3 inch. 



Locality and position. — Avicula-contorta sandstones at Pyle and 

 Stormy Down. 



This shell never exceeds the above small dimensions ; it generally 

 occurs in the form of casts. It is both gregarious in great numbers, 

 and occurs singly. 



Note on the Madreporaeia fi^om the " Sutton Stone." 

 By P. Martin Duncan, M.B. Lond., Sec. Gr.S. 



The collection of Madreporaria from the base of the Sutton Stone con- 

 tains a considerable number of specimens, some of which are de- 

 rived fossils, and the others, generally in a very fair state of preser- 

 vation, indicate a lower coralliferous horizon than has been hitherto 

 noticed in the British Secondary rocks. 



A fine-grained white limestone with much calc-spar is the matrix 

 of the Secondary corals ; and the Palaeozoic are contained in a rougher 

 stone, more or less conglomeratic. The neighbourhood of the Car- 

 boniferous Limestone accounts for the presence of its fossils at the 

 base of the Sutton Stone ; and the derived species therein contained 

 are well known and characteristic. 



The species are : — 



1. Lithostrotion irregulare. ] 2. Amplexus coralloides. " 



These forms do not require any notice ; they are unlike any from 

 Mesozoic sources, and are very common in the Carboniferous strata. 

 The specimens of the fine-grained limestone which contain undoubted 

 Secondary corals are numerous, and the fossils are either well pre- 

 served or are in the form of casts. 



Pour species can be determined satisfactorily, or rather three 

 species and three varieties of a fourth, whose Alpine type is not pre- 

 sent. The subgenus of one other form can be recognized ; and in all 

 probability the numerous casts must be referred to it. The species 

 are unlike any hitherto discovered in JS'orth- western Europe, and, 

 with certain reservations, indicate a zone of Madreporaria which in 

 the Alpine Trias would be deemed St. Cassian. 



The great ^Monograph of the British Possil Corals,' by MM. 

 Edwards and Haime, does not contain a description of any species 



