Vol. 69.] BATHONIAN ROCKS OF THE OXFORD DISTRICT. 507 



Through the kindness of Dr. F. A.. Bather, F.R.S., I was able to 

 have sections cut of several echinoderm-spines, with the view of 

 identifying those seen in the rock-sections ; but, since I was unable 

 to obtain specimens from some of the commoner Bathonian genera, 

 it was found impossible to identify them. Sections across different 

 parts of the same spine show so different a structure, that no evi- 

 dential value can be attached to them, unless a very large number 

 be examined. 



In all the ooliths found in the Bathonian rocks, the concentric 

 layers are well shown, but no Girvanella structure has been seen ; 

 those from the coarse type of the Stonesfield Slates are by far the 

 largest, and usually show radial as well as concentric structure. 

 They are generally formed round shell-fragments or small rolled 

 fragments of rock, resembling the matrix in which they are 

 ■embedded. 



VII. Correlation, and Conditions of Deposition. 



The correlation of the exposures in the district are most readilv 

 seen by reference to the two subjoined tables (figs. 4 & 5, pp. 508 

 & 509); it therefore only remains to indicate their relation to other 

 areas, together with the conditions prevailing in the Oxford district 

 during their deposition. 



The Chipping-Norton Series appears to he purely local, and to 

 be represented only in the Chipping-Norton and Oxford districts, 

 while the Neseran Beds seem to be equivalent to the acuminata zone: 

 that is, just above the Fuller's-Earth Bock of Dorset (S. S. Buck- 

 man, in litt.) ; on the north-east they keep approximately the same 

 character, and are readily recognized as the Upper Estuarine Series 

 in the Great Northern Bailway cuttings north of Peterborough, 

 where one band, the Astarte Limestone, is paloeontologically and 

 lithologically almost indistinguishable from that seen at Ardley. 



The Stonesfield Slates are known in the Cheltenham district, 

 where between them and the Fuller's-Earth Bock occurs a very 

 fossiiiferous band crowded with Ostrea and Rliynchonella, which 

 Mr. Richardson designates * the MliynchoneTla-con'cinna Bed.' A 

 similar bed occurs above the Neseran Beds round Chipping Norton, 

 and at Ardley ; in the Calvert Boring it rests almost directly on 

 Chipping- Norton Limestone, and at Stonesfield on the Stonesfield 

 Slates. 



The Fuller's-Earth Bock, both of Somerset and of the Cottes- 

 wolds, is characterized by Teloceras subcontractum, as are the 

 Weatherstones and Shell Beds of Minchinhampton, and appears to 

 ■come into line with Bed 31 at Ardiey (L. Richardson, in litt.). 



The whole group described as Upper Fullonian (Upper Beds of 

 fig. 5, p. 509) can be paralleled with the Great Oolite Clay and 

 ■Great Oolite Limestone resting on the Upper Estuarine Series north 

 •of Peterborough, where, however, lihj/nchonellce are practically 

 absent, although they are abundant in the same beds at Oundle. 



