78 



PROCEEDINGS COTTESWOLD CLUB 



1910 



Fig. I. — Map to show the position 

 of the Fuller's-Earth Section, near 

 Dyrham. (i inch = i mile). 



All these exposures, however, are insignificant. The only 

 good one now open is at the head of the little combe east 

 of Dyrham Wood, and distant about 

 a mile from the village in a southerly 

 direction. As this section is the most 

 important in the South Cotteswolds, 

 a sketch-map is given to show its pre- 

 cise position (text-figure i). The dot 

 at the eastern end of the wood under 

 the word " exposure " indicates its 

 position. 



The deposits exposed are beds of 

 argillaceous limestone, intercalated in 

 the usual kind of Fullers' Earth. They 

 abound in specimens of Ormthella 

 ornithocephala (Sow.), in all stages 

 of growth ; while the other fossils in- 

 clude Belemnopsis sp. (fragment), Ostrea acuminata, Sow., 

 Goniomya angulifera (Sow.), Isocardia nitida, Phillips, Rhyn- 

 chonella Sfnithi, Walker, Ornithella triquetra (Sow.), Serfula 

 plicatilis, Miinster, and Serpula quadrilatera, Goldfuss. 



Of good sections not now open may be mentioned those : 



(i) In the tunnel at Box :' 



(2) On the slopes of Lansdo\vn, when some excavations were being 



made : and 



(3) In the tunnel works east of Old Sodbury. 



It was from data supplied by the Box Tunnel that Lycett 

 arrived at his estimate of 148 feet for the thickness of the 

 Fullers' Earth in the neighbourhood of Bath. Mr H. B. 

 Woodward, F.R.S., has criticised it as being too great, because 

 none of the wells near Bath that he knew of had proved more 

 than 70 feet ;" but at the Monkswood Reservoir the Rev. H. 

 H. Win wood has found it to be between 150 and 180 feet 

 thick. 3 



A shaft in connection with the tunnel near Old Sodbury, 

 proved the Fullers' Earth — exclusive of 45 feet of " passage- 

 beds" into the Great Oohte — to be 90 feet thick, and to 



I "The Cotteswold Hills" (1857), p. 85. 2 Mem. Geol. Surv., "The Jurassic Rocks oJ 

 Britain," vol. iv. (1894), p. 93. 3 Proc. Bath Nat. Hist, and Antiqu. F. C, vol. vii. (1895), p. 150. 

 Prof. H. Reynolds and Dr A. Vaughan, Quart. Joum. Geol. Soc, vol. Iviii. (1902), pp. 740-742. 



