OF NORTH OXFORDSHIRE AND THE CLYPEUS-GRIT. 237 



Norton water-works, he saw this bed covered by yellow clays con- 

 taining an abundance of Ostrea acuminata. 



The Inferior Oolite of Sheet 45 N.W., mapped by the Geological 

 Survey as 5' g 7', and in part hitherto termed the " Northampton 

 Sand " of North Oxfordshire (C, D, and E of my section), may be 

 divided into (1) the marine and estuarine limestones of the Hook- 

 Norton type, (2) the Trigonia-signata bed, and (3) the Chipping- 

 Norton Limestone, which embraces all between the "signata" bed and 

 the Great Oolite. The greater part of the limestones of the Hook- 

 Norton type have been shown to overlie the Clypeus-grit at the Cross 

 Roads near Over Norton and in the Dip valley near Langdon Bridge, 

 and hence to the base of the Chipping-Norton limestone, at least, to 

 be well within the zone of Ammonites Parkinsoni. "Well-sinkings 

 have been noted at Chipping Norton by Mr. Windoes, yielding the 

 characteristic fossils of the Hook-Norton limestones, before the Cly- 

 peus-grit was reached. Whether the Chipping-Norton limestones 

 can be assigned to the ParJcinsoni zone is somewhat doubtful ; for, 

 with the exception of a large Patella and an Ammonite which 

 appears to be Amm. bullatus, D'Orb., recognizable fossils seem 

 not yet to have been found. Certainly in the mortar- like beds of 

 the Dip valley (Langdon Bridge), if not in the limestones below, 

 there is the dawn of a Bathonian fauna not so distinct in its facies 

 from the remains of the Great-Oolite beds above as from that of the 

 Inferior-Oolite beds beneath. In part, perhaps, the equivalent of 

 these beds above the Clypeus-grit may be found in the white oolite 

 above the Clypeus-grit of Mr. WitchelTs Stroud-hill section*, and 

 in those beds constituting the Inferior Bathonian of the Cote-d'Or 

 described by M. Jules Martinf. 



It will be remembered also that in the section quoted between 

 Notgrove and Bourton-on-the-Water sandy limestones with Tri- 

 gonia, and a clay-bed with plant-remains, intervene between the top 

 of the Clypeus-grit and the base of the Fuller's Earth. The base of 

 the Fuller's Earth in that section I have found to be full of water- 

 worn stones in crusted with Serpula?., rolled corals, numerous frag- 

 ments of Trigonia (including a fairly preserved Trigonia producta of 

 the Oxfordshire type), Nerincea, and Terebratula. These appear to be 

 the representatives of beds which I have shown to attain no incon- 

 siderable development eastwards. 



If, as seems to be probable, the Oxfordshire equivalents of these 

 beds underlie the Fullers Earth, they should belong to the Inferior 

 Oolite, notwithstanding an incoming of Bathonian fossils. How- 

 ever, Ammonites bullatus in the Chipping-Norton limestone has a 

 Bathonian look. 



Dr. Wright, in speaking of the eastern phase of the Clypeus-grit, 

 states that " it is not, as it has been figured and described by some 



* "Notes on a section of Stroud Hill," by E. Witehell, Esq., F.G.S. (Proc. 

 Cotteswolcl Field Club.) 



t Descr. du Groupe Bathonien clans la Cote-d'Or, par M. Jules Martin. 



