147

EXCURSION TO THE CHILTERNS.

SATURDAY, JUNE 3RD, 1905.

Directors: H. B. WOODWARD, F.R.S., F.G.S., and R. S.

HERRIES, M.A., F.G.S.

(Report by THE DIRECTORS.)

LEAVING Paddington at 9.15 the party arrived at LittleKimble at 11.12, where they found a telegram to say that theRev. E. C. Spicer, F.G.S .• who was to have acted as Director, wasunable to come. They subsequently learnt with regret that hehad met with a bicycle accident. By request of the membersMessrs. H. B. Woodward and R. S. Herries undertook thedirection of the party, and the excursion was carried out inaccordance with the programme.

The party proceeded through Great Kimble and ascended theChalk Downs by Piccadilly Hill and Pulpit Wood, just west ofChequers Court, traversing strata from the Upper Greensand ofLittle Kimble to the Upper Chalk at Pulpit Wood. Along this partof the journey the chalk appeared practically bare of surfacedeposits. and with very little soil. On a knoll of the MiddleChalk, Mr. Herries pointed out the leading features in the Vale ofAylesbury, a great dairy-land formed of Gault, Kimeridge andOxford Clays, with outlying hills of Portland and Purbeck Bedsand Ironsands, at Brill, Waddesdon, and elsewhere. The escarp­ment is here very bold and steep, intersected with small combes,and the speaker was of opinion that the scenery of the Chilternsonly wanted to be a little more known to Londoners to be asmuch appreciated as that of the North and South Downs.

On passing from the crest of the hills, which here attain aheight of 800 ft., the surface was seen to be formed of Clay-with­flints, and this accumulation was traversed for some distancealong the dip-slope of the Chalk. The track led throughpleasant beech-woods, with peeps of the deep valleys that intersectthe sloping chalk plateau, and give rise lower down to numerousstreams. Farther on the path led the members by HampdenHouse, formerly the residence of the celebrated John Hampden,and across a common to the region of Denner Hill, where thefirst noteworthy section was seen. Here some large blocks ofgreywethers or sarsen stones had been extracted from pits dug inan irregular mass of clay and flints. Iron rods had been used toprove the position of the greywethers, and pits were sunk hereand there to extract them. When found, the larger blocks werebroken and raised in separate portions, to be shaped afterwards

EXCURSION TO THE CHILTERNS.

into paving-sett s and curb-stones. One of these blocks was seenin situ in a pit about 20 ft. deep, embedded in the clay andflints, which is probably a disturbed mass derived partly from theClay-with-flints proper, and partly from formerly existing TertiaryBeds, as several Tertiary Pebbles were noticed among the heapsof stone dug out of the pit, and in association with the sarsens.

Proceeding then ce to the hamlet of Speen, a halt was madefor tea at the King William IV. Inn and afterwards the mem­bers examined several large excavations at Walter's Ash, on thenorthern part of Naphill Common. Here there were large pits,some 40 to 50 ft. deep, in brown-bedded brickearth overlaid bya stiffer brown and bluish-grey clay, with here and there irregularbeds of Clay-with-flints, occasional masses of mottled clay derivedfrom the Reading Beds, and greyweth ers of varying sizes and inall sorts of positions. Two industries are carried on here,that of brick-making, and that of dressing the stones for buildingand paving purposes. In one instance, at least, the huge grey­wethers presented the appearance of having subsided with otheraccumulations, mostly mottled clay and suban gular flints, into ahuge pipe in the Chalk, as described by the Rev. E. C. Spicer,·although the Chalk was not visible in the pit. The greywethershowever, were embedded in brickearth or clay and flints indiffer­ently, and the entire accumulation was regarded by Mr. Wood­ward as a wreck of Reading Beds and Clay-with-flints. A fewoutl iers of Read ing Beds still remain on the Chalk tracts awayfrom the main mass, and no doubt the strata formerly extendedover a wide area of the Upper Chalk. The destruction may havetaken place by flood-waters arising from the melting of ice duringthe Glacial period.

Mr. Herries agreed with Mr. Woodward, and though he thoughtMr. Spicer's theory that the occurence of the buried sarsen stoneswas to be accounted for by swallow-holes in the Chalk might insome instances be true, he did not think it was of general appli ­cation. It would, he said, be a curious coincidence that aconvenient swallow-hole should always be ready to absorb anysarsen. Moreover, in some of the pits seen by the members thebrickearth was very evenly stratified, and had not at all theappearance of having gone through the disturbance that would beinvolved in subs iding into a swallow-hole. He thought itpossible that th e brickearth (which was derived from nowdestroyed Tertiary outliers) had been laid down in still water,such as small lakes, into which the sarsen stone s had fallen, andthat this was followed by a more tumultuous rush of water whichhad brought the irregular clays and flints and some sarsen stoneson the top. H e regretted the absence of Mr. Spicer, who wasthus unable to present his views on the spot.

From Walter's Ash, by way of Bradenham, to the new station

• Quart. J ourn. Geol. S DC , vel, lxi, p, 39· ' 90S.

EXCURSION TO THE ISLE OF THANET. 149

at Saunderton, the members had to walk at an accelerated pacein order to catch the 6.15 train to Paddington. On the waysome large blocks of pudding-stone were noticed on the villagegreen of Bradenham.

REFERENCES.

Geological Survey Map, r-inch, Sheet 7, Drift. price 18s. 6d.Geological Survey Map, Sheet 7. Solid, price 8s. 6d.Ordnance Map. Sheet 255. 256. price IS. each.Index Map, Sheet 12. zs, 6d.1864. WHITAKEI<. W._u Geology of Parts of Middlesex , Bucks, " etc. Mem.

G~ol. Suroev,1887. Woonwxan, H. B.-uGeologyof England and Wales ," p. 449.1905. SPICER, E. C._u Sarsen Stones in a Clay Pit." Quart. Your,.. Geo],

Soc., vol. lxi, p. 39.

EXCURSION TO THE ISLE OF THANET.

WHITSUNTIDE, 1905.

JUNE 10TH TO JUNE J 3TH.

Director: W. WHITAKER, B.A., F.R.S., F.G.S., AND A. W.ROWE, M.B., F.G.S.

Excursion Secretary: G. W. YOUNG.

THE official party left Holborn Viaduct by the 5.10 p.m. train onFriday, June roth, and on arriving at Margate proceeded to theheadquarters at the Hereward Boarding House, Cliftonville.

SATURDAY, JUNE 10TH.

R~port by MR. WHITAKER.

The party, numbering twenty-five, left Margate by the 9. [4train for Herne Bay, and then walked at once to the coast.On getting beyond the town the general geological structure ofthe coast was explained . This is very simple, the beds steadilybut slowly sinking westward; so that whilst at Sheppey, to thewest, the London Clay at the highest point is capped byBagshot Sand, in an easterly course to the Reculvers, the bedsbeneath the London Clay rise up and soon appear in the cliffs,and beyond the Chalk also rises and at last appears at thewestern end of the Isle of Thanet.

The three divisions of the Lower London Tertiaries weresuccessively studied; but as the details of them have often beenprinted there is no occasion to reproduce them here. The Old­haven Beds (light-coloured sand with pebbles at the base) werefirst seen, cropping up from beneath the London Clay, and manyfossils were got in the masses of iron-sandstone and sandstone, sofrequent in them here, and so well to be seen in fallen blocksPROC. GEOL. Assoc., YOLo XIX, PART 3, 1905.] 12