128 



ME. S. S. BUCKMAN OIT THE BAJOCIAN [Feb. I9OI, 



for it stretches to Leckhampton Hill; tlie Lower Trigonia-grit 

 reacliiDg farther — its lower part, however, not extending to Crickley, 

 near Birdlip, though the rest of it does. 



The position of affairs may be roughly indicated in the appended 

 diagram (fig. 1) : — 



rig. 1. 



g 





ns 



o 







-tJ 





o 



a. 



v^ 



^ 



rickley. 

 eckham 



1 



SO 



o H 



O 



l^^ 





Lower Trigonia-gvit. 







Snowshill Clay. 





^^~~^- __^^ 



Harford Sands, 



Upper Freestone. 



~~~ ~- 



__^' 



After the Lower Trigonia-grit had been laid down, there was 

 continuous deposition of other strata, until the Phillipsiana-heds of 

 Cleeve Hill had been laid down. Then there occurred another — 

 the Bajocian — denudation, which again was most effectual in the 

 Birdlip district, where it removed a whole series of beds down to, 

 and perhaps lower than, the originally denuded Upper-Freestone 

 surface. When deposition again set in, and the Upper T^igonia- 

 grit was laid down, this deposit necessarily rested upon a denuded 

 surface of the outcrops of diverse rocks. 



II. Cause of the Bajocian Denudation. 



In my paper on ' The Mid-Cotteswolds ' (p. 431), I spoke of the 

 Bajocian denudation as having -cut out a wide, shallow trough 

 through the intervening beds of the Birdlip district. I was inclined 

 to think that the strata had not properly consolidated, and that 

 current-action might have swept away accumulations in certain 

 places. But I have found evidence that the strata just deposited 

 had consolidated. I obtained from the Cleeve-Hill plateau a bored 

 piece of Phillipsiana-heds, where the borings pass through shell 

 and stone equally : that implies that the stone was as hard as the 

 shell, otherwise the shell would have been avoided. The beds, 

 therefore, were thoroughly consolidated before the denudation. 



Then Prof. T. T. Groom, writing to me about my Mid-Cotteswold 

 paper, suggested that the previously-deposited strata had been 

 thrown into folds whereof the anticlines had suffered denudation, 



