236 THE GEOLOGY OF THE ISLE OF WIGHT. 



ment of peat has resulted from the form of the ground and the 

 issue of the springs which mark the outcrop of a clayey bed in the 

 Lower Greensand, as described on p. 45. 



Below Newchurch the alluvial flat is bounded by steep banks 

 of ferruginous sand (Lower Greensand), and is extremely irregular 

 in its boundaries, the river in its wanderings having undermined 

 first one bank then the other. The soil is of the usual dark 

 character, but there is no great thickness of peat. 



At Sandown the river must have been formerly joined by an 

 important tributary, for the alluvial flat, known as Sandown Level, 

 which branches off to the south, is at least as broad as that of the 

 main river. This tributary Alluvium runs only half a mile before 

 it is cut off abruptly by the sea, so that nenrly the whole of the 

 basin of the river which formed it has disappeared. The streams 

 of Shanklin and Luccomb Chines were probably some uf the head 

 waters of the river, and a little patch of gravel on the south side 

 of Shanklin Chine may have formed part of its valley deposits. 

 The tract of land on which Yaverland and Bembridge are 

 situated is isolated from the rest of the Island by this alluvial flat 

 and that of the Yar, and would be literally an island at high tide 

 in certain winds, but for the artificial bank along the seaward 

 margin of Sandown Level. It corresponds curiously to the " Isle 

 of Freshwater " at the opposite extremity of the Isle of Wight. 



Brading Harbour was continually inundated at high water until 

 the end of February 1880, when the sea was finally shut out by 

 the present permanent embankment, which encloses an area of 

 6U0 acres. Sir Hugh Middleton, iu the time of James I., 

 employed a number of Dutchmen to recover it from the sea by 

 embankments. 7,000/. were expended in the work ; but, partly 

 by the badness of the soil, which proved a barren sand, partly by 

 the choking of the drains for the fresh water, by the weeds and 

 mud brought by the sea, but chiefly by a furious tide which 

 made a breach in the bank, they were obliged to desist, and put a 

 stop to their expensive project {See Pennant's Isle of Wight, 

 vol. ii. p. 149). 



Near Lane End, Bembridge, a hollow in the older gravel con- 

 tains a newer peat and gravel. It Avas impossible to separate the 

 two gravels on the map and no determinable fossils were observed 

 in the peat, but these deposits seem to be merely the Alluvium 

 of the small stream which now flows through Lane End. 



The alluvial deposits of the smaller streams that flow into the 

 Solent consist of marsh-clays with trunks of trees, but in the 

 absence of clear sections there ia little to be said about them. It 

 may be pointed out, however, that the Alluvium of all the streams 

 descends far below their present beds. Thougli we have no means 

 of telling the full depth, yet judging by analogy, we should expect 

 that the old channels of the larger streams have been cut fully 

 40 feet deeper than their present ones, as is the case in most parts 

 of England. This indicates that their excavation dates back to a 

 period when the land stood at a considerably higher level. 



