THE BEACH AND "HEAD" OF THE CHANNEL ISLANDS 43 



instances the Loess is sufficiently argillaceous to 

 prevent the free percolation of the surface waters, 

 while at the same time it would favour the retention 

 of the salt. 1 



The Raised Beaches of Guernsey and Jersey.- 

 Before leaving the subject of the Loess, which would 

 require a volume to deal with fully, I may mention 

 another case which shows still more clearly the 

 insufficiency of river or rain agencies to account for 

 the presence of Loess in certain situations. Guernsey 

 and Jersey consist of hard slate and granitic 

 rocks rising to the height of 300 to 400 feet above 

 the sea-level, and forming plateaux ending on most 

 sides in high cliffs fronting the shore. These plateaux 

 are often covered by a deposit of brick-earth or Loess, 

 which attains in some places a thickness of ten to 

 twenty feet or more, whilst the cliffs are fringed by 

 remnants of a Eaised-beach from eight to twenty feet 

 above the level of the present beach. Originally 

 this old beach must have been continuous all round 

 the islands, which proves them to have been separated 

 from the Continent long before the period of the 

 Bubble-drift. Now only fragments of it remain at 

 intervals, and these are everywhere covered by a 

 Head, ten to thirty feet in thickness, consisting of 

 angular debris derived from the adjacent rocks, and 

 embedded in a matrix of the Loess from the plateau. 



It is evident from this that the deposition of the 

 Loess accompanied or preceded that of the Head. 

 It is evident also that owing to the absence of 

 1 See Appendix G. 



