1867.] DA^TKLN'S LOWER BRICK-EARTHS. 95 



among which Helicc nernoralis is to be fonnd. Eesting conformably 

 on this is a series of laminated grey and reddish clays (jS'o. 2), inter- 

 stratified with sand and fine seams of gravel, and containing vege- 

 table impressions, with the usnal shells and mammalian bones. The 

 latter are comparatively rare. The colour-bands of HeUx nemoraUs 

 are almost as brilliant as in the snails now living in our hedgerows. 

 At the top of this is a lenticular mass of shells (Xo. 3) of Unio jpicto- 

 rum, Cyclas, Pisidium, A/wylus, &c., decreasing from a foot to a thin 

 layer an inch in thickness, which passes in other parts of the pit 

 into a thin band of pebbles. In its upper part is a thin layer of 

 ferruginous gravel, composed of flint with a few pebbles of quartz. 

 From this point ^Ir. Etheridge obtained a nearly perfect lower jaw 

 of Eleplias anfiquus in 1864, which in company with him I saw in 

 situ along with the antler of a Eed deer and the skull of Bos jyrimi- 

 genius. It is the principal mammaliferous bed in the pit. As both 

 valves of the fresh- water sheUs are preserved in apposition, it is 

 evident that they lived on the spot where they are now found. A 

 grey laminated clay (Xo. 4) rests conformably upon Xo. 3, con- 

 taining a seam of gravel, composed of flint, with a few quartz pebbles, 

 and covered also conformably by Xo. 5, a series of false-bedded sands, 

 and lenticular gravel-beds without organic remains. Lying un- 

 conformably on these is (No. 6) a sandy irregularly contorted layer, 

 " the trail " of llr. Eisher, containing angular and waterwom flints, 

 large tabular masses of flint, and pebbles of quartz. Above this, 

 again, is the rain-wash, composing a surface-soil of from 2 to 3 feet 

 in thickness (Xo. 7). 



The threefold nature of the strata already noticed at Ilford is visible 

 also here. The beds from one to five inclusive are undoubtedly 

 the result of currents of fresh water free from gravel-laden ice, while 

 Xo. 6, as shown by the irregular size of its pebbles, its tabular fiints, 

 its contortions, and its irregular deposition, owes its presence to ice 

 in some form or other, and was not formed under the same conditions 

 as the fiuviatile beds below. Its sandy nature may be owing to the 

 Thanet Sand (which forms the northern boimdary of the brick-pit) 

 having been caught up by the ice and deposited on its melting, just 

 as the clayey nature of the trail at Ilford was probably owing to 

 portions of the London Clay being in like manner transported. The 

 rain-wash is the product of the disintegration of the deposits at a 

 higher level under a temperate climate. To the south of this 

 pit is another, near Little Thurrock, which is devoid of organic 

 remains. 



Xone of the bones are rolled, or mutilated in any way ; and all 

 present the appearance of having been dropped directly from carcases 

 swept down by some ancient river, in the exact positions in which 

 they are now found. Among other curious remains of mammals are 

 the coprolites of Hycena spelcm, which, so far as I know, have not been 

 discovered in any other river-deposit. 



y. Crayford. The next series of Brick-earths that comes bo- 

 fore our notice is that situated on the south side of the Thames, 

 fully 6 miles in a straight line from Grays Thurrock ; it occupies 



i2 



