THE TECHNOLOGIST. [Oct. 1, 1864. 



ON WORKING THE BATH FREESTONE. 133 



tion and probable condition ; and when it is known that uniformity of 

 condition over any large area is of extreme uncertainty, and knowing 

 as we do that the thinning out of the marketable beds of freestone in 

 this district, like the great oolite en masse on the line of deposition and 

 clip, is a fact now well understood, it becomes a matter of high import- 

 ance to the capitalist to be assured and confirmed as to the chances of 

 success in opening out or developing a new district. The natural 

 grouping of the beds constituting the great oolite series in this district 

 fall under three well-marked divisions, all well exhibited in the sections 

 exposed at Murhill, Westwood, and Farleydown, Combe and Hampton 

 Downs, Box and Corsham workings, &c, &c. Indeed, generally where 

 conditions have exposed them, and reading downwards from the surface, 

 we meet with over the Bath area, immediately below the forest of 

 marble (where present), the following groupings : — 1. The Upper Rag- 

 stones. 2. The Fine Freestone, or Building Beds. 3. The Lower Rag- 

 stone. These constitute a series from 60 to 120 feet in thickness, 

 depending upon local circumstances and conditions during deposition 

 and perhaps subsequent denudation. 



The Upper Ragstones. — This series consists of (in the upper part) 

 coarse, shelly, and irregularly bedded limestones, with usually a few 

 underlying beds of white fine-grained limestones, possessing a distinctly 

 and well-defined oolitic structure and finely comminuted shells ; these 

 are again succeeded by tough argillaceous beds of limestone, usually 

 pale brown in colour and smooth in texture, the whole ranging in 

 thickness from twenty-five feet to about fifty feet. No beds of workable 

 value occur in this upper series. 



The Fine Freestone, or Building Beds, in the Bath Stone Series. — Suc- 

 ceeding the upper ragstone are the Bath freestone, or fine-grained build- 

 ing beds, which vary in the number and thickness of the various beds 

 comprising the series, and also economically distinguished from each 

 other by their structural condition, the size and structure of the oolitic 

 grains, the presence or absence of silicious particles or finely divided 

 shelly matters, each of which may materially affect the limestone 

 during the process of working, or influence them after being placed in 

 position, and subject to weathering under atmospheric changes. In 

 some localities the beds assume an earthy structure, indistinct in texture, 

 smooth and close-grained, and hold more moistness. 



The Lower Ragstone. — Below the fine building beds, or freestone 

 series, are the lower ragstones, which appear to be persistent every- 

 where over the entire area, and resting upon the fuller's earth. They 

 consist of numerous and generally well-defined beds of a coarse shelly 

 texture, and hard crystalline limestone exhibiting much false bedding, 

 especially near the base. Many species of mollusca occur in the bottom 

 beds, such as Ostrea acuminata, Terebratula, Ornithocephala, Rhyn- 

 chonella, Trikitis, Concinna, and Tancredia. These lower ragstones, as 

 before mentioned, rest immediately upon the fuller's earth, but this 



