484 MR. M. ODLLNG ON THE [Oct. I913, 



22. The Bathonian Rocks of the Oxford District. 

 By 11. Odling, M.A., B.Sc, F.G.S. (Read May 7th, 1913.) 



[Plates XLVII & XLVIIL] 



Contents. 



Page 



I. Introduction 484 



II. General Description 484 



III. Details of Sections 488 



IV. Palaeontology 501 



V. Chemical Composition 504 



VI. Petrology 506 



VII. Correlation, and Conditions of Deposition 507 



I. Introduction. 



This -work was undertaken at the suggestion of Prof. Sollas, who- 

 supervised the work, and at his suggestion a large number of 

 rock-sections have been examined. 



To Mr. W. W. Fisher, M.A., Public Analyst for Oxfordshire, 

 Berkshire, & Buckinghamshire, I am indebted for much help and 

 many valuable suggestions in carrying out the chemical analyses. 

 I must also express my thanks to Mr. Linsdall Richardson for 

 kindly verifying a number of my identifications, and for his help 

 in the correlation of the beds with those of other districts. 



My thanks are also due to Mr. R. C. Sikes, M.Inst.C.E., for 

 permission to visit the Ardley Cutting, and to the Directors of the 

 Oxford Portland-Cement Works, who, contrary to their regulations, 

 readily granted me permission to examine their quarry. 



II. General Description. 



The rocks described in this paper form a well-defined series 

 sharply separated from the underlying beds, consisting of the 

 Ciypeus Grits on the west and Northampton Sands on the east ; 

 and from the Oxford Clay, which nearly always conformably 

 succeeds. 1 



Throughout the series there is a general westward thickening, 

 especially marked in the lower members of the Great Oolite. 



1 In the Calvert boring, the whole of the Cornbrash is missing ; see A. M. 

 Davies & J. Pringle, Q. J. G. S. vol. lxix (1913) p. 333. The description 

 of the strata in that boring suggests to my mind the absence also of the 

 lowest beds of the Oxford Clay of the district — the beds that probably 

 represent the Kellaways Clay. 



