Vol. 59.] AT COWLEY, NEAK CHELTENHAM. 385 



This extent is, I think, very limited. There is only one section, 

 namely, at Cuckoo-Pen Quarry, where these two subdivisions 

 are seen in juxtaposition ; and there the Lower Trigonia-Grit 

 is only 3 feet 2 inches thick. The reasons why a very limited 

 area might be anticipated are as follows. At the close of the 

 hemera bradfordensis, and consequently of the Aalenian Age, the 

 deposits were thrown into a series of flexures, with the result that 

 at Birdlip there was an anticlinal axis. Denudation of the Birdlip 

 anticline proceeded for a considerable time, and continued while 

 the Harford Sands, Snowshill Clay, and Lower Trigonia-Grit (pars) 

 were being deposited farther north. At Leckhampton Hill the 

 Snowshill Clay is seen to have overlapped the Harford Sands, and 

 to rest non-sequentially upon the Upper Freestone. At the same 

 locality, but a little farther to the west, the Snowshill Clay is 

 absent, and the Lower Trigonia-Grit rests directly upon the Upper 

 Freestone : the lower portion of the Lower Trigonia-Grit being 

 markedly conglomeratic. It is now necessary to look for a higher 

 horizon in the Lower Trigonia-Grit upon which further to de- 

 monstrate this overlap. At Charlton Common the Aidacothyris- 

 Meriani-Bed occurs 16 inches above the base of the subdivision ; 

 at Tuffley's Quarry it has been fixed at 8 inches above the 

 base : while at Cuckoo Pen it has not been observed, although 

 a diligent search has been made. At all events, there is a noticeable 

 decrease in the thickness of the deposits of the hemera Discitce : and 

 this being due to overlap, it follows that the reduction is attributable 

 to the Upper Freestone not having been sufficiently submerged to 

 allow of the accumulation of sediment. At Cuckoo Pen, however r 

 the Lower Trigonia-Grit has been denuded during the Bajocian 

 Denudation also. At Tuffley's Quarry 10 feet 2 inches of deposit 

 separate the Upper Trigonia-Grit from the Upper Freestone : at 

 Cuckoo Pen the thickness of the intervening deposit is but 3 feet 

 2 inches. Tuffley's Quarry is distant about 6 furlongs from that 

 at Cuckoo Pen. 



The causes producing the Bajocian Denudation appear to have 

 been forces so acting as to effect a repetition of flexures along old 

 lines of weakness, and thus in the Birdlip area we may again locate 

 an anticline. This time, however, the elevation was much greater : 

 it may be measured by the fact that the Upper Trigonia-Grit 

 rests upon the Upper Freestone ; indeed, the level of the Aalenian 

 Denudation was passed by the Bajocian. If so much deposit 

 was removed in the short distance between Tuffley's and 

 Cuckoo-Pen Quarries, it would appear that so thin an accumulation 

 as the Lower Trigonia-Grit — reduced in thickness between Leck- 

 hampton and Birdlip, owing to the fact that it overlaps the Upper 

 Freestone, as already demonstrated — would soon be denuded ; in 

 other words, the extent, from the place where the Upper Trigonia- 

 Grit rests upon the basement-bed of the Buchmani-Grit to where 

 it rests upon the highest part of the Upper Freestone, would not be 

 very great. Indeed, it is improbable that it exceeds half a mile i 



