•1870.] Fullers-Earth. 69 



At Bridport, on the coast of Dorsetshire, the Fuller 's-Earth attains a 

 thickness of 150 feet ; and near Bath, where it forms a conspicuous 

 band, it is 140 feet thick; at Wotton-under-Edge, 128 feet; near 

 Stroud, 70 feet ; and in the north of Gloucestershire, as near Chelten- 

 ham, it is further reduced to a general thickness of from thirty to 

 forty feet. It appears at Sherborne, near Burford, to the north- 

 east of Cheltenham, and does not extend as far east as Oxfordshire, 

 beyond which the Stonesfield slate rests on the Inferior Oolite. 

 The horizontal extension of the typical Fuller 's-Earth in the south- 

 west of England, which is about 180 miles, is very much the same 

 as that of the Upper Lias Sands — preserving a maximum thickness 

 from Bridport to Bath, but attenuating rapidly to the north and east, 

 and finally thinning out a little to the north-east of Cheltenham. 



Lithology. — The peculiar mineral from which the formation 

 derived its appellation, is confined to particular districts, as around 

 Bath and Stroud, and where it does occur, constitutes but a very 

 small portion of the thickness of the formation. This Fuller' s-Earth 

 is used in fulling cloth. The lithological characters of the formation 

 may be gathered from the following sections : — 



1 . Cliff at Watton Hill, west of Bridjport Ha?'bour, " composed 

 principally of blue clay, grey marl, and marlstone, with subordinate 

 beds of imperfect stone; thickness of 150 feet; the base reposes on 

 the Inferior Oolite, and the formation is covered by the Forest - 

 Marble."* 



2. Bath, in descending order : — 



Feet. 



A. Blue and yellow clay, with nodules of indurated marl 30 — 40 



B. Bad Fuller' s-Earth 3 — 5 



C. Good Fuller'' s-Earth 2 5— 3 



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



of nodular limestone and indurated marl . . . . 100 



135-5—148 



Bed D encloses one or two strata of a tough, rubbly limestone, 

 which is commonly called Fuller's-Earth rock, and bears considerable 

 resemblance to Cornbrash. This rock is always accompanied by an 

 immense number of Terebratulm, and My a angulifera and Isocardia 

 concentrica are almost invariably found in it.f 



3. Slaughterford, East Gloucestershire : J — 



Feet. 



White marls, with occasional stonybands 25 



White and grey limestone, and Fuller's-Earth rock .. 10 

 White and blue calcareous clays with Tercbratuloz . . 30 



65% 



4. Near Cheltenham. — The deposit consists of regularly bedded 

 blue and yellow shales, clays and marls, with occasional courses of 



* Be la Beche and Buckland, ' Trans. Geol. Soc.,' 2nd series, vol. iii. (1830). 

 t Lonsdale, Geol. of Bath, ' Trans. Geol. Hoc.' 

 % Hull, Mem. Geol. Surv., sheet 34. 



