74i Geological Society : — 



2. " On the Western Extremity of the London Basin ; on the 

 Westerly Thinning of the Lower Eocene Beds in that Basin ; and 

 on the Grey wethers." By William Whitaker, Esq., B.A., F.G.S., 

 of the Geol. Surv. Great Britain. 



In the first part of this paper the author described certain outliers 

 of Tertiary strata in the neighbourhood of Bedwin and Savernake 

 >(or Marlborough) Forest, in Wiltshire, where in the course of the 

 Geological Survey of the district he found that both the Woolwich 

 and Heading Beds and the London Clay gradually thinned out 

 westward, until merely 3 or 4 inches of the latter alone remained 

 between the Bagshot Beds and the Chalk. Further eastward these 

 are probably in direct apposition. The superficial loam and clay 

 with unworn flints on the Chalk district along the northern side of 

 the London Basin were then described. 



In the second portion of the paper it was shown, both from the 

 published results of Mr. Prestwich's researches and later observa- 

 tions made in the progress of the Geological Survejr, that the Thanet 

 Sands thin out westwardly, from a thickness of about 85 feet in the 

 Isle of Thanet, to about 35 feet at London, and to 3 feet at Chob- 

 ham, disappearing altogether near Epsom. The Woolwich and 

 Reading Beds include the Blackheath Pebble-bed, according to the 

 author : at Heme Bay Mr. Whitaker gives these beds a thickness 

 of about 50 feet, at Croydon 45 feet, at New Cross 54 feet, at 

 London from 40 to 70 feet, at Ealing 60 feet, at Hanwell 75 feet, 

 at Chiswick 90 feet, at Reading about 50 feet, and near Great Bed- 

 win in Wiltshire only 15 feet. The London Clay, with its Basement- 

 bed, is nearly 480 feet thick at Sheppey, 400 feet at London, 370 feet 

 at Reading, 20 to 60 feet near Newbury, only 15 feet near Great 

 Bedwin, and is represented by a few inches of its pebbly basement- 

 bed in Marlborough Forest. 



The third part of the paper treated of the Greywether Stones of 

 Wiltshire, which the author believes must have come from the 

 Bagshot Sand, which alone of the Tertiary Beds is present there in 

 sufficient thickness to yield these large and numerous masses of 

 bedded rock. 



3. " On a Clay-deposit with Insects, Leaves, &c. near Ulverston." 

 By John Bolton, Esq. 



The deposit described in this paper was a greenish-drab clay, 

 lying beneath a capping of locally derived drift and rubble of varying 

 thickness, upon the Mountain -limestones of Low Furness. It was 

 met with during the progress of drainage-works undertaken by the 

 Lindal-Cote Iron-ore Company. At one locality, the clay is 93 feet 

 from the surface, and has a thickness of 15 feet; it seems to fill a 

 basin in the limestone. The imbedded plant- and insect-remains 

 and its contained Diatomacese proved the deposit to be of lacustrine 

 origin. Fragments of wood occurred in it, stained blue by phos- 

 phate of iron. It appeared probable from the depth at which the 

 clay was buried beneath locally derived material, upon a compara- 

 tively level surface, that it was of great antiquity, though possibly 

 younger than the glacial epoch. 



