296 JURASSIC. 



Plant-remains have been recorded, including Pterophyllmn, Zamites, 

 and Pakwzamia. 



Professor R. Tate regarded the Fuller's Earth as the uppermost 

 zone of the Inferior Oolite;^ but the fossils indicate that it is 

 closely connected with the Great Oolite, and in Dorsetshire the 

 Upper Fuller's Earth seems to replace that formation. 



The thickness of the Fuller's Earth in Somersetshire varies from 

 120 to 180 feet. At Scale Hill, near Bruton, the following section 

 was noted by De la Beche : ■ — 



Upper Fuller's Earth 133 feet. 



Fuller's Earth Rock 25 ,, 



Lower Fuller's Earth 21 ,, 



Lamyat Beacon is a conspicuous outlier of Fuller's Earth Clay 

 and Rock. The Fuller's Earth is largely developed in Dorsetshire 

 (400 feet). A good section (about 90 feet) of grey crumbling marl 

 is shown in the somewhat treacherous cliffs of Watton Hill, between 

 Eype and Bridport Harbour, where the beds, overlaid by the 

 Forest Marble, are faulted on the west against the Middle Lias and 

 on the east against the Midford Sands. In both cases the faults 

 run in an easterly and westerly direction. The junction of Fuller's 

 Earth and Inferior Oolite is shown in the cliff at Burton Bradstock. 

 (See Fig. 40, p. 252.) The Fuller's Earth contains beds of impure 

 limestone, and (near the faults) layers of fibrous carbonate of 

 lime, like the " Beef" of the Purbeck Beds. Bivalves of the 

 genera Lucina, Alyacites, Nucula, etc., are met with in the marl. 

 A bank almost entirely composed of specimens of Ostrea acuminata 

 is exposed on the borders of the Fleet, south of Langton Herring, 

 near Weymouth. Fossils have also been obtained from a cutting 

 at Smokeham, near Poorstock.^ 



The Fuller's Earth Rock is well exposed in the railway-cuttings 

 east of INIilborne Port, and between Wincanton and Cole, near 

 Shepton Montague. In this neighbourhood it makes a conspicuous 

 escarpment. In Gloucestershire the Fuller's Earth has a thick- 

 ness of 130 feet at Wotton-under-Edge, 70 feet at Stroud and 

 Sapperton Tunnel, while it occurs only as a thin band at Chelten- 

 ham. The upper layers in this district are frequently interstratified 

 with beds similar to Great Oolite. (See Fig. 44, p. 280.) Fossils 

 have been obtained at Cubberly, near Cheltenham, at Sapperton, 

 etc.^ 



The Fuller's Earth soon disappears when traced beyond 

 Gloucestershire ; but it is represented by a few feet of clay at 

 Chipping Norton, and at Sherborne near Burford on the borders 

 of Oxfordshire. 



^ Quart. Journ. Science, 1870, vii. 68. 



- Mem. Geol. Survey, vol. i. p. 2S0. 



^ See T. Wright, Q. J. xii. 310 ; R. Damon, Geol. Weymouth, 1884, p. 223. 



* E. Hull, Geol. Cheltenham (Geol. Surv.), p. 52. 



