219 



lower zone, near Calne and Lynham. Everywhere the coral 

 rag or middle zone has the character of being an ancient 

 coralline sea-bed, interposed between two arenaceous deposits, 

 (the upper and lower calcareous grits,) and is remarkable for 

 the vast assemblage of reef-building polypifera, and the tests, 

 spines and debris of Echinidse it contains compared with the 

 small proportion of Mollusca found with them. 



Steeple Ashton, Wilts, was long a famous locality for corals. 

 The surface of the fossiliferous beds of the Coral Eag were 

 there exposed in many fields, and the corals annually ttirned 

 out by the plough were exposed to the air and weathered. I 

 have collected the following species from this locality : — 



CoEALS FROM StEEPLE AsHTON. 



Stylina tubulifera, Phil, Goniocora sociaKs, Edem. 



II Delabechii, Ediu. & Raime. Isastrsea explanata, Gold/. 



Ttecosmilia annularis, Keferstein. Thamnastrsea arachnoides, Park. 

 Calamopliyllia Stokesii, Edw. & Haime. " concinna, Goldf. 



Cladopliyllia Conybearii, Ed. & Haime. Conioseris irradians, Edw. & Haime. 



The Coral Rag at Farringdon, Berks, consists of irregularly 

 bedded coralline Limestone, with beds of clay intercalated 

 therewith ; the corals are, for the most part, species of 

 Thamnastroea, Thecosmilia, and Isastrcea, &c., lying in the 

 position in which they grew in the lagoon of the coral sea. At 

 Marcham, Garford, Fyfield, and Bradley, near Cumner, there 

 are several quarries of this rock. At Headington, a good 

 section of the whole series is obtained. " The formation here 

 divides itself into a lower and upper series. The lower beds 

 are of the more usual description, and are well shewn in a 

 quarry 100 yards south of the WindmiU, near Workhouse 

 Farm. They are formed of enormous quantities of fragmentary 

 corals, "besides Conchifera, in great abundance. The corals are 

 of the genera Thecosmilia and Isastrcea, &c., and are generally 

 imbedded in thin coatings of clay. In this section the thick- 

 ness of the rock is 12 feet, and at the base we find the soft 

 brown sands of the lower calcareous grit. Further to the 

 north-east we find the higher beds of the coralhne Oolite well 



