THE RAISED BEACHES, CLIFF AND RUBBLE HEADS 

 OF GUERNSEY. 



BY MR. A. COLLENETTE, F.C.S. 



The elevations have been ascertained by levelling from mean sea -level by 

 John James Carey, Esq., F.K.G.S. 



The object of this paper is to give an account of the superficial 

 deposits of the island so far noticed by the Society, or by any 

 of its members, such deposits having attracted but little 

 attention on the part of geological authors, who appear to 

 have been satisfied with a passing glance and a rather hasty 

 deduction. The present paper will deal with the matter in a 

 systematic manner, but will necessarily be but introductory, 

 for this field of enquiry may be said to have just been opened, 

 and therefore the information conveyed must necessarily be 

 incomplete. As far as I know there exists no previous 

 account of these deposits, though many authors have alluded 

 to them when writing on such formations in other places. I 

 think I may safely say that the longest notice of these form- 

 ations as they exist on this island is to be found in a paper 

 read before the Geological Society on January 22, 1851, by 

 R. A. C. Austen, Esq., F.R.S., " On the Superficial Accumula- 

 tions of the Coasts of the English Channel" 

 I shall first describe the 



RAISED BEACHES. 



These are mere patches or remnants not yet destroyed by 

 the rapidly advancing sea, which in many cases has nearly 

 succeeded in sweeping away the deposit, and in one or two 

 cases has succeeded in destroying extensive deposits and 

 removing their very last remnant. 



The patches of " raised beaches " exist nearly all around 

 the island, as far as we have levelled them, are found to range 

 between 23 feet and 65 feet above mean sea-level. 



The part of the coast which has, so far, yielded no evi- 

 dence of a raised beach, at any elevation, is the stretch of cliff 

 between Pleinmont and Icart on the south side of the island. 



All around the coast, and even well removed inland, we 

 find these evidences of a former sea-level, or possibly it would 

 be more correct to say of former sea-levels. At 



