648 AIR. j. V. ELSDEN ON THE SUPERFICIAL GEOLOGY OF 



angular, and there is but little admixture of ironstone. No trace 

 of stratification is to be noticed, and the gravel sometimes makes 

 huge pockets in the Greensand below (see diagram, fig. 8). It is 

 interesting to find this bed of gravel rigidly confined to the 100 feet 

 contour, which extends from Selmeston to Berwick Station, where 

 sections are again visible in the railway-cutting. On descending 

 this ridge and ascending again to a similar level on the isolated hill 

 at Mayo the flint-drift reappears, capping the hill, but not a trace 

 is to be seen in the lower grounds to the north around Ripe and 

 Laughton. Approaching the Cuckmere river there is only one 

 locality in which the 100 feet contour is reached, and this on a small 

 hill immediately overlooking the river, about half a mile south- 

 west of Sessingham. The altitude here is 110 feet, or nearly 

 90 feet above the level of the river, and this hill is again capped 

 with angular flint-gravel. This is so evidently an outlying patch 

 of the gravel at Selmeston and Berwick Station that it is noticed 

 here, although the locality is well within the Cuckmere basin. 

 The Selmeston gravel extends southwards as far as Berwick church, 

 overlapping the Gault and part of the Upper Greensand. 



Thus in the Ouse basin we find an exact repetition of the 

 phenomena observed in the basins of the Arun and Adur, viz., well- 

 defined river-gravels bordering the streams at various altitudes, and 

 traces on the watersheds of an old plateau-drift which furnished 

 part of the materials for the giavels of the lower levels. 



The Cuckmere Basin. — The gravels which have just been 

 described as occupying heights of 100 feet or more above the 

 sea-level at Berwick Station are intimately connected with other 

 beds at a lower level, which seem to be of undoubted river-origin. 

 The reason for the close proximity of these gravels is to be found in 

 the narrowness of the Cuckmere valley and the small distance 

 intervening between the river and its watershed. The lower gravel 

 is to be seen on descending the hill at Berwick church, towards 

 Lower Berwick. Prom this point it extends past Winton to 

 Alfriston in a narrow band, fringing the river at between 25 and 

 30 feet above its present level. On the opposite side of the river, at 

 Milton Court, it occurs again, and several patches of angular flints 

 are to be found higher up the river, as at Highfield Bank and 

 Milton Bam. Near Milton Crossing a good section of this lower 

 gravel is to be seen in a cutting south of the railway, where 3 or 

 4 feet of loam and gravel, full of angrilar flints of all sizes, rest upon 

 an uneven surface of Lower Greensand. There are here distinct 

 traces of stratification, although the flints are very angular. This 

 bed of gravel covers the 50 feet contour close to the river. Similar 

 gravel occurs at the same elevation on the opposite side of the river, 

 and again near Chilver Bridge, where the whole of the 50 feet level 

 is thickly covered with angular flints. 



Between this point and Michelham the banks of the river consist 

 of low mounds of loam, with many very small "Wealden fragments 

 and a few flints ; but at Michelham Priory there is a small bed of 

 river-gravel, chiefly composed of waterworn Wealden pebbles 



