438 MR. D. FIDGEON ON CERTAIN PECULIARITIES OF 



2Q. On CERTAIN Physical Peculiarities e.vhibited hy the so-called 

 " Eaised Beaches " of Hope's Nose and the Thatcher Rock, 

 Devon. By D. Pidgeon, Esq., F.G.S., Assoc.Inst.C.E. (Read 

 April 30, 1890.) 



(Abridged.) 



The so-called " Raised Beaches " of Hope's Nose and the Thatcher 

 Rock, near Torqua}^ have been so often discussed by eminent geolo- 

 gists that no attempt will be made to add anything by way of 

 description in a paper proposing to deal exclusively with certain 

 physical peculiarities exhibited by the " beaches " in question. 



The word "beach" may be defined as an accumulation of sandy, 

 shelly, and pebbly materials brought together, by the action of 

 waves, upon the shore ; while " raised beaches " are similar accu- 

 mulations which since their formation have been lifted above the 

 present level of the sea. 



These definitions being granted, the author proposes to show, in 

 the first place, that certain physical considerations, applicable to 

 both of the " raised beaches " in question, make it impossible to 

 consider them as beaches at all ; and, in the second place, to suggest 

 a possible explanation of their origin. 



The considerations in question first struck the writer while 

 working out the Conchology of the beaches for his friend Mr. A. R, 

 Hunt, of Torquay, who has embodied the results thus obtained in a 

 speculative paper on " The Raised Beach on the Thatcher Rock : 

 its Shells and their Teaching " *. He gives a list of 43 species, with 

 notes on their distribution in the present seas. 



Referring, in the first instance, to the stony constituents of the 

 beach, it will be observed — 



1. That all the hand-samples exhibited to the Meeting are com- 

 posed of fragments of rock and shells, both of which, with scarcely 

 an exception, exhibit sharply fractured edges and are without any 

 stratification. 2. That the rock-fragments consist, almost exclu- 

 sively, of limestone derived from the cliffs overhanging the so-called 

 beach ; and that they are exactly such splinters as would fall, under 

 the influence of weather, and particularly of frost, from those cliff's. 

 3. That the number of pebbles, properly so-called, in the beach is 

 quite insignificant ; and that, of these, very few are composed of the 

 local limestone, chips of which constitute nearly the whole of the 

 stony component of the deposit. 4. That stones other than lime- 

 stone occur very sparingly and consist of quartz, Triassic trap. 

 Devonian sandstone, and flint ; and that, of these, very few are 

 rounded, although some were once pebbles, which had been fractured 

 before finding their way into the " beach." 5. Of the very few 

 rounded stones of any kind, one here and there is incrusted with 

 Annelidan tubes, acquired under water, and not since removed by 



* Trans. Devon Assoc, vol. xx. pp. 225-252. 



