VOL. XVIII. (2) MEMOIR. MAP OF CHELTENHAM 131 



The Lower Freestone is well exposed in the large quarries. 



Its commercial uses are dealt with later (p. 132). 



The Oolite Marl contains an interesting series of brachiopods, 

 which may be sought for at (32). 



The Snowshill Clay is clearly exposed at only one place in the 

 district under consideration — on Charlton Common (33). 



The Lower THgonia- and Buckmani-Grits are very rich in 

 fossils. In the former, on Charlton Common, at (34), at 2 fact 10 inches 

 above the top of the Upper Freestone, is a thin marly layer crowded 

 with specimens of Aulacothyris meriani (Oppel). The Gryphite-Grit 

 is well-known. It is extensively used for the top-stones of walls and 

 specimens of its characteristic oyster are prominent in weathered 

 masses. The rock is seen at (35) and {36), where detached oysters 

 strew the ground. The Notgrove Freestone is relatively thin at 

 Leckhampton Hill. Its top-bed is riddled with annelid borings, as 

 may be very well observed in the shallow working (37) on the summit 

 of the hill, where it is overlaid by the Upper Trigonia-Grit. 



Gravel on the Hill-sides. — The greater portion of 

 the superficial extent of the Upper Lias in the neighbourhood 

 of Leckhampton Hill and Charlton Common is covered with 

 gravel. In the gravel, here and there, are great masses of 

 Oolite, which have become detached and have slipped down 

 from the main mass above. 



It has not been an easy matter to map this gravel. Traces 

 on the clay-land of the Vale, insufficient to represent by a 

 separate colour on the map, and irrespective of age, are in- 

 dicated by the symbol (G). 



Subsidence, fracturing, slipping and complete detach- 

 ment of masses of Oolite, is not infrequent on the Cotteswold 

 edge. 



On the eastern side of Charlton Common is a slipped 

 mass of rock, chiefly Pea-Grit. Mountains-Knoll Wood covers 

 similar rock plus Lower Freestone. 



The old workings along a line drawn southwards from 

 (24) are instructive. They show very clearly indeed the 

 faulted condition of the rock on the hill-side. 



At (29) is a slipped mass of Pea-Grit ; at (38) of Lower- 

 Freestone ; and at (39) of Freestone, but on the horizon of 

 the Roestone. 



Gravel encompasses these masses. The more recent ad- 

 ditions to the gravel are angular ; but, as I have mentioned 

 elsewhere, the older portion is much more " granular.'" 



I Proc. Cotteswold Nat. F.C. vol. xvii., pt. i (1910), p. 40. 



