58 MR SMITH ON THE CHANGES 



in Cornwall under the name Ixr/g, as an island connected 

 with the mainland by a space covered every tide, but dry 

 at low water, — a description which would apply accurately 

 at the present day. In Scotland, the Roman wall, which 

 crosses the island from sea to sea, has evidently been form- 

 ed at both ends with reference to the present level. The 

 same observation applies to British tumuli and vitrified 

 forts, which are perhaps of still greater antiquity. It is, 

 therefore, highly probable, that no changes of level have 

 taken place since the British islands have been tenanted by 

 man. 



We have ample proof that traces of these changes occur 

 in every part of our coasts. In England, the observations 

 of Messrs Phillips, * Rose,-f- Robberds,| Sedgwick,§ &c, 

 on the east coast ; Messrs Mantell,|| De la Beche, IF Sedg- 

 wick, and Murchison, ** on the south ; and Sir Philip 

 Egerton, Messrs Murchison, Gilbertson, &c, -f*-f- on the 

 west, shew, that in all parts of the English coasts they are 

 to be met with. In Scotland, in addition to the Notices in 

 the Wernerian Memoirs, already adverted to, the Statistical 

 Account abounds in direct or incidental notices of similar 

 phenomena. My own observations, and those of every well 

 qualified observer, confirm their universality in this part of 

 the island. 



In Ireland, I have seen them on the east, north, and 

 west coasts. I am informed by Mr Griffiths, that he has 

 observed them in Cork and Waterford, and Captain Port- 

 lock has recently found them in stratified beds at an eleva- 



• Geol. of Yorkshire, vol. i. p. 23. t Phil. Mag. Jan. 1836, p. 30. 

 $ Phil. Mag. March 1827, p. 223, &c. 

 § Geol. Soc. Proceedings, vol. i. p. 409. 



|| Geol. of Sussex, 285. Geol. Proc. ii. 203. II Geol. Manual, 149. 

 ** Proc. Geol. Soc. Dec. 1836. tt Fourth Report Brit. Assoc, p. 654. 



