1803.] IIOLL INFERIOR. OOLITE. 307 



may approximately be placed upon the parallel of the Cheltenham 

 ferruginous pisolite."* 



More recently, Dr. Wright communicated to the Geological Society 

 a paper in which these lower beds at Dundry form the type of his 

 " zone of Ammonites Humphriesiaruus" while the white-oolite beds 

 above constitute his " zone of Ammonites Parkinsoni" The former 

 he has referred to the horizon of the Upper Freestone of the Northern 

 Cotteswolds, and the latter to that of the Trigonia- and Gryphitc- 

 gritsf. 



The result of my own investigations is at variance with each of 

 these views ; and, having followed the beds stratigraphically along 

 the line of their outcrop, I shall endeavour to show that their true 

 position is higher in the series than is stated by any of these geolo- 

 gists, and that they arc, in fact, the southern extensions of the 

 Upper and Lower Ragstoncs of Mr. Hull, the uppermost of which is 

 not represented in the typical section at Leckhampton, having risen 

 above the level of the country, and cropped out before reaching the 

 brow of the hills. 



Southern side of the Mendips. — On the southern side of the Mendips 

 the Inferior Oolite nowhere exceeds 28 or 30 feet in thickness, of 

 which from 8 to 10 feet belong to the lower subdivision. The upper 

 subdivision immediately underlies the Fuller's Earth ; and its light 

 colour, lithological structure, and general poverty in organic remains 

 readily distinguish it from the hard, brown, more or less massive or 

 rubbly limestone beneath, which is everywhere very fossiliferous. 



Both members are well exposed in quarries and lane-side sections, 

 along the whole length of the belt of oolite as it ranges through 

 Dorsetshire and Somerset, but especially so in the neighbourhood of 

 Bridport, Yeovil, Castle Gary, Bruton, and, further to the north, at 

 Batcombe, and on the hills east of Shepton Mallet. At the " Half- 

 way House," between Yeovil and Sherborne, we find the following- 

 section, which fairly represents the general characters of both sub- 

 divisions : — 



Section at the "Halfway House" 



A. Upper Ragstone. Thin-bedded oolite, with partings of brown, 



sandy, laminated clay 13 



B. Lower Ragstone : — 



1. Hard, ferruginous, thick-bedded limestone, divided near 



the middle by a soft, friable, light-coloured band .... 6 



2. Hard, light-coloured, fine-grained, sandy limestone .... 3 



The upper part of B contains many Ammonites; and the soft friable 

 band which divides the bed contains several species of Gasteropods 

 in a fine state of preservation, and also Collyrites ring ens, C. ovalis, 

 Hyboclypus gibberidus, Terebratula PJiiUipsii, T. sphoeroidalis, Rhyn- 



* ' Cotteswold Hills,' p. 72, 1857. See also Proceedings of the Cotteswold 

 Club, vol. i. (1853) p. 64. 



f " On the Subdivisions of the Inferior Oolite of the South of England, com- 

 pared with the equivalent beds of that Formation on the Yorkshire coast," 

 Quart. Journ. Geol. Soc. vol. xvi. pp. 17 & 24 (1859). 



