426 Mr. Winch on the Geology of Lindisfarn. [Dec. 
Articte III. 
Remarks on the Geology of Lindisfarn, or Holy Island. By 
N.J. Winch, Esq. Honorary Member of the Geological Society 
of London, and of the Mineralogical Society of Dresden. 
With a Plate. (No. XVIII.) 
(To the Editor of the Annals of Philosophy.) 
SIR, Newcastle-upon-Tyne, Nov. 1, 1822. 
Previous.y toattempting adeseription of the geological struc- 
ture of Lindisfarn, it may notbe amiss to mention a fewleading par- 
ticulars respecting the island, which will at least save the trouble 
of referring to printed authorities on the subject. The venerable 
Bede, who wrote in the eighth century, calls Lindisfarn a semi- 
island, being surrounded by the sea twice every 24 hours; and 
a popular poct of the present day delineates this striking phe- 
nomenon in the following lines : 
«¢ The tide did now its flcod-mark gain, 
And girdled in the saint’s domain ; 
For with the flow and ebb, it still 
Varies from continent to isle ; 
Dry shod, o’er sands twice every day, 
The pilgrims to the shrine find way ; 
Twice every day the waves efface 
Of staves and sandal’d feet the trace.”” 
Ages have passed away since the time of Bede, and but little 
alteration seems to have taken place during the long interval, 
either on the western side of Holy Island, or on the opposite 
coast of Northumberland—a clear proof of the sea having made 
ng considerable inroads for centuries on the indented shore of 
this part of England, and warranting the supposition that the 
Farn islands and Staples must have been divided from the main 
land by the agency of a temporary current of water sufficiently 
strong to break up and remove the adjoining strata of limestone, 
shale, and sandstone, but not powerful enough to destroy the 
more obdurate masses of basalt which have been thus left in 
their present isolated situations. 
The length of the island from north to south including a pe- 
ninsula called the Snook, is about two miles and three quarters ; 
its breadth from east to west, a mile and ahalf.. The town con- 
tains about 500 inhabitants, of whom 70 are fishermen, usually 
engaged in the white-fish or herring fisheries, but acting occa- 
sionally as pilots, many of them being legally authorized by 
the Trinity House at Newcastle. The harbour is extensive and 
safe, except during heavy gales of wind from the westward ; it 
has eight feet water on the bar at low water, and twenty-two 
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