Vol. 63.] XIMERIDGE CLAY AND CORALLIAN ROCKS OF BRILL. 29 



2. The Kimeridge Clay and Corallian Bocks of the Neighbour- 

 hood of Brill (Buckinghamshire). By Arthur Morley 

 Da vies, A.R.C.S., B.Sc, F.G.S. (Read November 21st, 1906.) 



[Plate I.] 



Contents. 



Page 



I. Introduction 29 



II. The Eid's-Hill Section 30 



III. The Arngrove Stone {Bhaxella- Chert) 37 



IV. Palaeontological Notes 43 



I. Introduction. 



A few miles east of Oxford the Corallian limestones and sands 

 disappear abruptly, and for a long distance to the east and north- 

 east the whole of the Upper Jurassic Series between the Cornbrash 

 and the Portland Beds consists of clay, with some local rock-beds 

 intercalated here and there. With this disappearance of stone 

 comes a great falling-off in the number of exposures ; therefore 

 it is not surprising that, while the Portland and Purbeck Beds of 

 Brill and Aylesbury have attracted much attention, the strata 

 below them have been neglected by geologists. In the Geological- 

 Survey memoir on the Middle and Upper Oolitic rocks of England 

 (1895), Mr. H. B. Woodward ends a brief account of the district 

 between Wheatley and Quainton with the sentence ' Further re- 

 search in the district is desirable ' (p. 135). It is as a contribution 

 to this further research that this paper is offered. 



The eleven years that have passed since that memoir was pub- 

 lished have brought some changes to the district. At that time 

 perhaps the most difficult of access of any so near to London, it is 

 now traversed by two main lines of railway, while a third is on the 

 point of being constructed. Large brickfields have been opened up 

 for the supply of London and the residential districts of Buckingham- 

 shire. On the other hand, the closing of small stone- and brick-pits 

 continues, to the sorrow of the geologist. 



I began the study of the strata below the Portlandian in this 

 district in 1899, and have visited it nearly every year since. 

 Though most of my work has had to be carried on alone, I have to 

 acknowledge my hearty thanks to my friends Messrs. J. H. Pledge, 

 J. Guest, and E. W. Pocock, for help in the field-work and the 

 pleasure of their companionship. To Mr. Pledge I am further 

 indebted for the photomicrographs which illustrate this paper. To 

 Mr. J. J. UfF, the manager of the Brill Brick & Tile Company, 

 my thanks are due, not only for the full permission kindly given 

 to work in the Company's brickfield, but also for much information 

 readily imparted. 



I am particularly indebted to Mr. G.,C. Crick for the trouble that 



