GEOLOGY. 9 



do from Oborne. This seems to be supported by the fossils, because if we look 

 through d'Orbigny's ' Paleontologie francaise (Cephalopodes) ' we find none of what 

 might be called the fossils peculiar to Bradford Abbas represented ; the real fact 

 being that of the species figured by d'Orbigny, probably Am. Sowerbyi is the only 

 one which came from the zone of that name, and it is this zone which is so fossili- 

 ferous at Bradford. St&phanocer as Hum<phriesianum has been found at Bradford in 

 the bed No. 3, but it is rare and generally very poor, so that roughly speaking the 

 Fauna at Bradford Abbas is totally distinct from that at Oborne. There seems, 

 therefore, to be in the south a parallel to the Normandy beds, both in fossils and 

 characters, and also to the Cotteswold beds in fossils, but not in character. 



I need scarcely remark on the correlation of the two sections given above, as it 

 seems to be evident from the sections themselves. Practically identical lists of 

 fossils have been obtained from the various beds allocated in each quarry to 

 the same horizons or zones, 1 and these lists of species having been compiled, 

 after particularly observing the exact position from which every species that I 

 collected was taken, I am enabled to definitely assign the zone to which the beds 

 belonged. It is interesting to note the occurrence of Rhynchonella ring ens in both 

 places. The Oborne and Bradford Abbas' quarries are the types of the two classes 

 of Inferior Oolite rocks to be met with in the south-west. In one class it is the 

 Sowerbyi-zone that preponderates and is most fossiliferous, while in the other 

 it is the Humphriesianum. 



One bed of which there seems to be no representative in the south is the 

 Oolite marl. It is in fact a most difficult matter to say with what it should be 

 correlated. It is true that in the south Terebratula curvifrons has been found in 

 the Murchisonge-zone, but it is rather different in shape from the one found in the 

 Oolite marl of the Cotteswolds. At a quarry on Corton Downs in Somerset there 

 is a blue clay with bands of stone in it, much resembling the blue parts of 

 Oolite marl shown at Notgrove Station, Gloucestershire. This clay is quite stiff 

 and some 3 — 4 feet thick. It contains, however, the usual fossils of the Sowerbyi 

 bed at Bradford Abbas, Lioceras concavum (Sow.), Terebratula Eudesi, Bh. 

 Forbesi, fyc, being found there, but we have never seen anything at all like the 

 Fauna of the Oolite marl. 



As regards the thickness of the Inferior Oolite rocks in the South of England : 

 They probably at no one place from the zone of Murchisonas upwards occupy more 

 than 40 feet, although of this we cannot be certain. Just to the north of 

 Sherborne in Dorset the Parkinsoni beds are quarried and expose a thickness 



1 I ought here to explain that the Humphriesianuni-zone is fossiliferous both at Oborne and Wyke 

 quarries, and that the list of fossils mentioned refers more particularly to this bed. At Oborne the 

 Sowerbyi-zone has yielded but few fossils, but enough to identify it. "Wyke quarry differs from 

 Bradford Abbas in having the Humphriesianum-zone fossiliferous. 



