part 1] GAULT AlS^D LOWEil GREEjS^SAND neae leightoi^. 21 



The Silty beds : — Thickness in feet. 



^ 



^5 



-3 ^ 12 



^4 



2 c. Banded silty greyisli-wliite sand, darker grey carbonaceous loam~ 

 and streaks of siltj'- clay: the whole weathering buff and 

 loamj^ at the outcrop : some thin tabular claystone con- 

 cretions with ferruginous crust, up to 1 foot in length ; also a 

 few smaller sandy pyritous nodules, on definite bedding-planes.J 



2b. Streak^^ gvey and buff loam and fine ash-coloured sand, witlO 

 impersistent green streaks and streaks of coarse washed sand 

 up to an inch or two thick ; some imperfect tabular ferruginous 

 concretions along la3^ers, and a few fine-sandy pyritous nodules, 

 decomposing : claye}'- streaks in the lower part. 



2 a. Ashy-grej' carbonaceous silts, with clay-streaks and streaky fer-~ 

 ruginous induration forming imperfect cakes of sandy iron- 

 stone; with a 2- to 3-inch band of interlaminated wet carbon- 

 aceous greyish-brown silt and greasy-feeling gre}' clay at the 

 base ; resting sharply and unconformably on — J J 



Silver Sands, cross-bedded and coarse in the upper part, finer below : seen to 18. 



Dr. Kitchin & Mr. Pringle mention the occurrence of ' a few 

 dark phospliatic nodules ' about halfway down in the stratified 

 Silty beds (2b of the above section), and on the strength of this 

 they regard part of the beds as ' of tardefitrcata-2u^Q ' {op. cit. 

 pp. 57-58). I made close search, both in this and in another section 

 ( Double Arches pit, p. 24) in which the series is well-developed, 

 but failed to find in the Silty beds any phosphatic nodule of the 

 kind described. The gritty phospliatic nodules in the Miletree 

 Farm pit are confined, so far as I have seen, to the gritty green- 

 sand-loam and muddy grit associated with the ironstone-breccia 

 (3 & 3a). The point is of consequence in the general interpre- 

 tation of the sections (see p. 55). The Silts contain specks of 

 vegetable matter in plenty, but have as yet yielded to me no 

 identifiable fossil. 



The sections of the pits above described, from Harris's pit on 

 the west to Miletree pit on the east, are combined in the reduced 

 section, fig. 13, p. 22, which is at right angles to the other reduced 

 section, fig. 12, on the same page. It misses the Silty beds on the 

 east side, and runs mainly along the belt of irregular iron-grit 

 crags, except at the western end, where the craggy belt swings 

 50 to 100 yards farther south. 



Sections north-east and north-west of Shenley Hill.— 

 About half a mile north-east of the Shenley Hill j^its there is 

 another group of pits near some farm-buildings named ' The 

 Poplars' on the 6 -inch Ordnance map, where the road from Leighton 

 joins the cross-road from Heath to Watling Street (see fig. 1, p. 2), 

 the intervening tract being at present unbroken. One of these is an 

 extensive re-working of an old pit, now known as ' Double Arches,' 

 opposite the junction of the roads, and the other two are new 

 excavations a little farther eastwards. The more easterly of these, 

 which I shall call ' Poplars pit,' reveals the base of the Grault 

 (fig. 14, p. 23) ; the western part of ' Double Arches ' shows a good 

 section in the Silty beds over the Silver Sands, but has not reached 

 the Gault ; the middle pit, at a lower level in the shallow valley 

 which runs between the pits just named, is entirel}'' in Sands and 



