SO-CALLED " RAISED BEACHES " IN DEVON. 439 



the attrition of a beach. 6. The limestone chips are entirely free 

 from Annelidan incrustations and borers' holes. 7. On the other 

 hand, fracjtnents of what were once small limestone pebbles, riddled 

 by borers, occur in some numbers ; no bored limestone pebhles, 

 however, are found. 



Turning now from the stony to the shelly components of the 

 deposit, these latter demonstrate — 



8. That about half the mass consists of shelly matter. 9. That 

 the shells, with scarcely an exception, are fractured, exhibiting 

 peculiarly sharp and sometimes razor-like edges. 10. That the 

 bulk of the shelly component consists of rock-dwelling shells, such 

 as Litorina and Furjnwa, derived from the Laminarian- and higher 

 zones ; and that a large proportion of these rock-dwellers are un- 

 broken. 11, That, on the other hand, all the sand-dwelling Bivalves 

 in the deposit are broken into fragments. 12. AVhether whole or 

 broken, however, all the shells retain their sculpture to a very re- 

 markable extent, some allowance being made for chemical erosion. 

 There is hardly a beach-rolled shell, and very few beach- rolled 

 fragments of shell, in the collection. 13. Xo Annelidan incrusta- 

 tions occur on the unbroken shells, and very few on the fragmental 

 Bivalves — another indication that both came, for the most part, into 

 the beach as " live " shells. 14. While the facies of the fort3'-three 

 shells obtained by Mr. Hunt is generally that of the present Mol- 

 luscan fauna of Torbay, one decidedly Northern shell {Troj)ho)i trun- 

 catas, and one less decidedly northern (Pleurotoma turricula) occur 

 in the list. These two shells might, perhaps, be taken to indicate 

 a rather colder sea in the era of the raised beach. 



Nothing could be more unlike a true sea-beach than the breccial 

 deposit thus characterized. As to its stony constituents, nothing 

 need be said ; the splinters of local limestone speak for themselves ; 

 but, with regard to the shelly components, it may be remarked : — 



1. The shells most abundant in this breccia, namely the rock- 

 dwellers, are usually rare on the shore, and a beach of which Pur- 

 jmra and Litorina form an even appreciable proportion is unknown. 

 Further, such rock-dwellers, when found on beaches, arc always 

 beach-rolled. 2. Bivalves, which are generally much more nume- 

 rous than Gasteropods on beaches, are usually found with parted 

 valves, but otherwise unbroken ; and a beach upon which all the 

 Bivalves are fragmental, while most of the Gasteropods are whole, 

 does not exist. 3. Such broken shells as occur on existiug beaches 

 have their fractured edges always waterworn ; but many of the 

 beach shells, the Purpurea especially, exhibit almost razor-like edges. 



Before attempting any explanation of the origin of the Hope's 

 Nose and Thatcher Beaches, it will be well to formulate certain 

 questions which any such explanation must answer under pain of 

 being inadequate. 



As to the stony constituent of the beaches, it must say: — 



1. Why are the limestone chips, wliich constitute the chief com- 

 ponent of the deposit, sharply angular ? 2. AVhy, if they be por- 

 tions of a true beach, these fragments exhibit no signs of beach- 



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