BLOWN SAND. 237 



Blown Sand. 



The largest nrea. of Blown Saud in the Isle of Wight is to be 

 found on the top of the verlical chfF between Atherfield and Chale, 

 at a height of 150 to 250 feet above the sea. The sand is blown 

 up from the face of the cliff, not from the beach below, and con- 

 sists merely of disintegrated Lower Greensand. Several sections 

 in it have been noted above in describing the gravel below it 

 (p. 234) ; the greatest thickness of it seen was about 20 feet, but it 

 probably exceeds this in parts of the line of dunes which it forms 

 alou"; the edo;e of the cliff. It extends also for some hundreds of 

 yards inland in the form of a thin covering of dusty sand. The 

 most westerly patch of this sand lies on the outcrop of a bed of 

 iron-sand, and contains vast quantities of spherical grains of iron- 

 oxide derived from it. 



On either side of Ladder Chine the sand is piled up in small 

 hammocks or dunes, and, if we descend into the chine, the source 

 of the sand becomes sufficiently obvious. The chine ap})ears to 

 have commenced its existence as a small notch cut by the surface- 

 drainage from the adjoining fields. The wind, especially that from 

 the south-west, entering the notch has gradually widened it out 

 into a beautifully symmetrical amphitheatre, leaving the harder 

 beds and concretions standing out in tiers of benches, but whirling 

 every loose particle of sand up over the top of the cliff. The 

 chine thus provides an interesting illustration of wind-erosion, 

 comparable on a small scale to the scenery of parts of the desert 

 region of Western America.* 



Very small spits, consisting partly of blown sand, extend half 

 way across the alluvial flats of the western Yar and of the Newtown 

 estuary. At the mouth of the eastern Yar a more extensive tract 

 of Blown Sand rises here and there into small dunes, used for the 

 Golf Links, and serves to protect Bembridge Harbour on the 

 north-east side. The sand travels in all cases from west to east. 



Chalk Talus. 



At the foot of the slopes of the chalk hills a gravelly detritus 

 of chalk has accumulated to a considerable thickness. It is well 

 seen in Compton Bay, v.'here the steepest part of the cliff in 

 which the Upper Greensand crops out is formed by a stratified 

 chalk talus, or rain-wash, from the slopes of Afton Down. The 

 deposit here reaches a thickness of 20 teet, and is compact enough 

 to stand in a vertical cliff. The second exposure is seen in the 

 road-cutting between Brixton and Calbourne, where the talus has 

 spread itself over the Upper Greensand, and become hardened. 

 The third occurs on St. Catherine's Hill, on the summit of Gore 

 Cliff. In this locality the deposit consists of hard calcareous mud, 

 attaining a thickness of about 1) feet, and becoming harder and 



'^ As was remarked to the writer by Mr. G. K. Gilbert, of the United States 

 Geological Survey, during an excursion to this locality. 



