154 MR. S. S. BUCKMAN ON THE BAJOCIAN [Feb. ipOI, 



VIII. Summary. 



(1) The Bajocian denudation was brought about by slight elevation 

 of the rocks due to small carthi-moveraents, causing a main south- 

 westerly to north-easterly axis of elevation, and subsidiary 

 north-westerly to south-easterly axes. 



(2) Such removal of strata almost as soon as they have been 

 deposited may be called ' penecontemporaneous erosion.' 



(3) The chief fenture of the North Cotteswolds is the development 

 of strata between the Upper Freestone and the Lower Trigonia- 

 grit: the strata being Harford Sands, a somewhat thick series of 

 fissile stone called the Tilestone, and Snowshill Clay. 



(4) Another feature is the loss of the Phillipsiana-io- Witchellia-hedLB 

 (inclusive) in the main-hill mass, owing to erosion. 



(5) The Upper Trigonia-grit rests upon Notgrove Freestone over the 

 greater part of the area. The evidence that the Notgrove Free- 

 stone extended over the northern part of the district is important 

 for mapping the denudation. 



(6) The Notgrove Freestone is, in the northern part of the area, 

 distinguished by the abundance of Pecten personatus (?) and by 

 the occasional occiirrcnfe of Trlgonia signata. 



(7) Gryphite- and Terebratala Btickmani-grita are present, but only 

 exposed on the western flank. 



(8) The Lower Trigo)iia-gnt is considerably altered in lithic 

 character. 



(9) The influence of penecontemporaneous erosion in the making 

 of the Vales of Bourton and Moreton is considerable. 



(10) Such erosion is likely to have taken place along similar lines 

 at different times, and therefore may be connected with folds in 

 the Palaeozoic rocks, and may have a bearing on the thickness of 

 the rocks overlying the Coal- Measures. 



(11) The dates of various penecontemporaneous erosions show that 

 during Jurassic times there were constant small elevations of 

 certain areas. 



EXPLANATION OF PLATE VI. 



Map of the Bajocian Denudation corrected to April, 1900; on the 

 scale of 4 miles to the inch, (See p. 146.) 



Discussion. 



Prof. Geoom complimented the Author on his valuable results. 

 He had been over some of the ground with the Author, and con- 

 sidered that a good case had been made out for a break in the luferior 

 Oolite ; but he thought that the relation of the upper to the lower 

 part of that series should be described by the simple term 'uncon- 

 formity.' 



Mr. H. B. WooDWAKD remarked that anyone who discussed the 

 Author's paper should follow rather than precede him over the 

 ground which he had so carefully and minutely described. While 



