( 113 ) 



4. On the rapid Dimmution of the Sand-banks in Mount's Bay.* 



The great extent in former periods of the sand-banks on the 

 east and west of Penzance, has been already noticed in the 

 Transactions of this Society. t These banks, so recently as 

 within the last fifty years, presented on the sea-side of the 

 high road two beautiful walks of green turf, varying in breadth 

 from about 40 feet to nearly as many fathoms — the one 

 stretching more than two miles between Penzance and Mara- 

 zion, and the other one mile from Penzance to Newlyn — 

 each being continuous, with the exception of an occasional 

 opening for communication with the beach. 



Seventy years ago a meadow lay outside the present sea- 

 wall at the entrance to Newlyn ; and about the same period 

 were several houses and gardens in Penzance seaward of the 

 cottages at " Sandy-bank ; " but of these extremities of the 

 old " Western Green " not a vestige is now visible. A mi- 

 nute description of what remained of the western bank in 

 1826 was given in the third volume of the Transactions.:}: 

 In order to preserve the portion still left within the limits of 

 Penzance, the Corporation in 1843 completed a strong wall, 

 forming the sea-side of a noble terrace-walk or esplanade, 

 half a mile in length, which promises to be a permanent bar- 

 rier against all further encroachments of the sea. The east- 

 ern bank is also rapidly diminishing, but no sea-wall has yet 

 been required. Numerous rocks, lying between high and low 

 water, which forty years since were always buried four or 

 five feet beneath the sand, are now uncovered : this applies 

 to the beaches below both sand-banks, and is particularly 

 observable near Newlyn, Chyandour, and Marazion. 



The effect of this disappearance of the sand, and of the 

 consequent deepening of the water along shore, is very re- 

 markable at the causeway leading from Marazion to St 

 Michael's Mount. This causeway, or ridge of shingle and 

 sand, is evidently formed by the confluence of the waves 



* Vide Transactions of the Royal Geological Society of Cornwall for 1847. 

 t Vol. ii., p. 130. ; I'age IG7. 



VOL. XLV. NO. LXXXIX —JULY 1848 H 



