468 



Mr. Austen on the 



Stromatopora concentrica, Gold. Petref. Germ. 



polymorpha, Gold. id. 



Fenestella, Lons. (Retepora, Gold.) Silur. St/st. 



abnormis, Lo7is. id. 



antiqua, Lons. id. 



Retepora infundibulum, Lons. id. 



prisca, Gold. Petref. Germ. 



Lithodendron, Gold. id. 



CBBspitosum, Gold. id. 



Amplexus, Soiv. Min. Con. 



tortuosus, Phil. Pal. Foss. 



Cyathophyllum turbinatum, Gold. Petref. Germ. 

 Cystiphyllum (Cyathophyllum, Gold.), Lons. 



Silur. S>/st. 

 Damnoniense, Lo7is. Geol. Trans. 



vesiculosum. 



Strombodes, Sclnveigger Beobachtungen, S^c. 



vermicularis, Lons. Geol. Trans. 



Astraea, Linn. 



ananas, Gold. Petref Germ. 



helianthoides, De Plain, 



Hennahii, Lons. 



pentagona, Lons. 



Porites, Lamarck. 



pyriformis, Lons. Silur. Syst. 



Coscinopora, Gold. 



placenta, Gold. Petref. Germ. 



Favosites, Lamarck. 



fibrosa ( Calamopora), Gold. Pet. Germ. 



Gothlandica, Lam. Anim. sans Vert. 



polymorpha, T (Calamopora) 



spongites, J Gold. Pet. Germ. 



<J 2. Red arenaceous slaty strata. — The slate range, subjacent to the coral limestone, 

 requires only a short notice, as any description would be purely mineralogical, and 

 details of those local variations common to all deposits, have now little interest or 

 value attached to them. These slates and shales are remarkably deficient in organic 

 remains over wide areas, but productive localities occur in the parishes of East and 

 West Ogwell, Denbury, Berry Pomeroy, the neighbourhood of Torquay, and in 

 Mudstone Bay. They suggest the notion of slow and tranquil deposition, and an uni- 

 form condition as to depth ; while the casts of molluscous and other animals, whose 

 most delicate markings are admirably preserved, indicate that the sedimentary matter 

 was in an exceedingly minute state. It is only with the red arenaceous portion, which 

 often resembles the old red sandstone of Herefordshire, that different conditions are 

 required, — such as would produce alternations of conglomerates, sandstones and 

 shales. Near Broad Sands is an included calcareous bed, composed of rounded 

 blocks of limestone imbedded in a hard matrix ; the blocks show that at this early 

 epoch, lime rocks had been formed in some quarter ; but, in the absence of organic 

 remains, it is impossible to say, whether they were conveyed from a distance, or 

 were derived from some reefs existing in the vicinity. 



Although the slates and coral limestones both belong to the same geological period, and were probably 

 in many instances contemporaneous deposits, the suite of organic remains of the slate system differs 

 widely from that of the coral limestones, a change, the natural result of the different habits of marine 

 animals. Thus the Terebratulce, which so swarmed about the reefs where they had the means of fix- 

 ing themselves, that we find twenty-three species in the Newton quarry alone, are altogether wanting 

 in the slate. The constancy of certain forms to rocks which indicate similar conditions is very remark- 

 able ; thus we find the same Fenestella, Turbinolice, Pleurodyctium problematicum, &c., ranging through 

 the whole middle slate district of South Devon and continued into Cornwall ; but it would be impossible 

 in a local memoir to enlarge on the subject of the connexion constantly to be observed between the 

 mineral character of rocks and the forms of the inclosed organic remains. The large Strygocephali of 

 South Devon evidently covered extensive surfaces, as oyster-beds do now, thick strata being entirely 



