GREAT OOLITE. 297 



Economic products, etc. 



The following section by Lonsdale exhibits the general type of the Fuller's 

 Earth near Bath :^ — 



Feet 



4. Blue and yellow clay, with nodules of indurated marl 30 to 40 



3. Bad Fuller's Earth 3 to 5 



2. Good Fuller's Earth zh to 3 



I. Clay containing beds of bad Fuller's Earth, and layers 



of nodular limestone and indurated marl 100 



An old analysis of Fuller's Earth showed about 73 per cent, of silicate of 

 alumina, and 27 per cent, of carbonate of lime ; some ferruginous matter was also 

 present.^ 



Mr. H. W. Bristow has observed that the blue Fuller's Earth is frequently of 

 as good quality as the yellow for particular purposes, as in fulling coarse cloths, 

 but the yellow is usually esteemed the better. The general thickness of the veins 

 is from iS inches to four feet. If good, a vein 18 inches in thickness could be 

 worked with profit, but not if of less thickness. Sometimes the vein ends 

 suddenly ; at others it gradually thins out. 



The economic Fuller's Earth has been worked along the outcrops of the strata 

 at Dunkerton, Odd Down, near Midford, Wellow, and Box. Shafts with levels 

 are sometimes sunk to a depth of thirty feet or more. The earth has been much 

 used in fulling at the cloth mills at Bradford-on-Avon, Frome, and in Gloucester- 

 shire. It is still worked in the district near Bath. In Gloucestershire the earth is 

 only occasionally represented by an impure and useless bed. 



The Fuller's Earth rock is quarried for building-purposes, for road-metal and 

 for lime-burning. Bricks and tiles are sometimes made from the Fuller's Earth 

 clay, as at Maperton, south-west of Wincanton ; and the clay is also burnt for 

 ballast between Toller Porcorum and Poorstock. 



The soil is not, as a rule, very fertile, the land being heavy and wet. On the 

 slopes of the Cotteswold Hills the soil on the Inferior Oolite is sometimes largely 

 made up of slipped Fuller's Earth, and its fertility is thereby improved. 



The Fuller's Earth throws out copious springs, and has caused numerous slips on 

 the declivities of the hills around Bath and other places. 



Great Oolite Series. 



The Series is divided as follows : — 



Cornbrash. 



Forest Marble and Bradford Clay. 



( Lower Zone. Stonesfield Slate and Northampton Sand 

 (upper part). 



GREAT OOLITE. 



The Great or Bath Oolite consists of a series of shelly limestones 

 (rags) and fine oolites or freestones, often exhibiting much false- 



^ T. G. S. (2) iii. 249 ; see also Geol. East Somerset (Geol. Surv.), p. 125. 

 - C. Boyd, Letters, etc., Bath and West of England Soc. (1810) xii. 379. 



