328 



J. F. BLAKE A^D W. H. HUDLESTON OX 



we may notice that in Irton Lane the same phenomena occur in an 

 equally indubitable manner, -where the appearances are such as would 

 lead us to suppose that 14 feet of Coralline oolite, with numerous Ne- 

 rinceoe, observed on the dip-side of a strong coral reef, were deposited 

 at the same level as the reef, or even partly above it. Leaving this 

 matter, however, as unproved, the undoubted overlying of the oolite 

 on the Kag seems to indicate that in some parts of this district other, 

 later reefs may have been formed, which have now disappeared or 

 are only to be found in the more westerly portion of the vale. Cer- 

 tainly there are peculiar features in the fauna of this Rag. Cidaris 

 florigemma, that highly characteristic urchin, is never, to our know- 

 ledge, found in these beds, its place being taken by Cidaris Smithii. 

 We must also notice the extreme abundance of Phasianella striata, 

 elsewhere not abundant in the Rag, but in the oolite below. It is 

 remarkable also that the prevailing coral is Thamnastrcea concinna, 

 to the exclusion of almost any other form except Rhabdophyllia. 



These beds may be traced as far as Brompton, where they have a 

 similar character, and continue to yield a large and interesting suite 

 of fossils. 



There is nothing to be seen along this r?nge which could represent 

 any higher beds, such as the Upper Calcareous Grit, the great 

 thickness of well-stratified sand between Ruston and "Wykeham being 

 apparently a superficial deposit. That the Upper Calcareous Grit is 

 not entirely absent in the district, is manifest from the curious frag- 

 ment yet remaining on Silpho Heights ; its presence there may be 

 taken to indicate that it once had a greater extent in the district of 

 which we are now treating. 



Fossils of tlie Seamer-Ayton-Brompton Rag. 



Some of the more characteristic fossils of these Rag-beds, including 

 both the hard and the soft parts, and also certain brashy partings 

 are : — 



Natica arguta, Phil. (? clio, D' Orb.). 

 Cerithium inornatum, Buvig. 



limasforine, Bom. 



Humbert inum, Buv. 



Nerinsea fusif oralis, J)' Orb. 



fasciata, Voltz. 



Littorina niuricata, Sow. 

 Turbo funiculatus, Phil. 



corallensis, Buvig. 



Trocbus aytonensis, B. cf H. 

 Delpbinula muricata, Buvig. 



(Strickl. Coll.). 

 Pbasianella sti'iata, Sow. 

 Trocbotoma tornata, Phil. (cf. T. 



discoidea, Buvig.). 

 Bulla Baaugrandi, Be Lor. 

 Ostrea duriuscula, Phil. 

 Exogyra nana, Sow. 

 Ostrea gregaria, Sow. 

 Anomia, smooth species. 



Pecten vimineus, Sow. 



lens, Sow. 



Hinnites velatus, Gold/. 

 Lima fragilis, Bom. 



rudis, Sow. 



rigida, Sow. (small). 



Perna mytiloides, Lam. 

 Area quadrisulcata, Sow. 



pectinata, Phil. 



Cucullcea elongata, Phil. 

 ?Astarte aytonensis, Lye. 

 Myoconcba texta, Buvig. 

 Modiola inclusa, Phil. \ , 



Lycetti, Whit, j t)0rerS - 



Terebratula insignis, Schub. (juv.). 

 Pseudodiadema versipora, Phil. 

 Cidaris Smithii, Wright. 

 Hemicidaris intermedia, Flem. 

 Rhabdophyllia Edwardsi, M'Coy. 

 Thamnastrsea concinna, Phil. 



