4 THE INSULATION OF ST. MICHAEL'S MOUNT. 
During the visit I encountered an intelligent native, who, 
though in his eighty-third year, was still active both in mind and 
in body, and who stated that within his recollection there had 
been no encroachment on any part of the cliff under the shelter 
of the Mount; but he added that at a short distance eastward 
“the sea had destroyed a great deal of land.” On going with him 
to the spot, he pointed out an isolated rock on the tidal strand, 
which he said was so far in, and concealed by, the cliff when he 
was a boy of eight or ten years of age, that the portion of it which 
projected barely furnished him with a foothold from which, when 
bathing, the had frequently jumped into the sea at high water. 
From the data thus furnished I came to the conclusion that, where 
entirely unprotected by nature or art, the retrocession of the cliff 
had not exceeded twenty feet in seventy-five years; and that to 
suppose the Marazion cliff, from which the Mount cut off all 
destructive waves, had retreated at the average rate of ten feet in 
a century, would be to take a very high estimate. Taking this 
as a measure, and remembering that the distance from the main- 
land to the Mount is 1680 feet, it followed that the hypothesis of 
insulation by mere encroachment would require us to fix the date 
of the insulation at nearly seventeen thousand years ago. In other 
words, we should be at liberty to believe that about 150 centuries 
before the Christian era the permanent connexion of the Mount 
with the mainland was severed, but that immediately prior to 
that date it might have been a hoar rock at the end of a wood. 
To suppose it in, that is surrounded by, a wood, a further demand 
must be made on antiquity, such as would have sufficed for the 
wasting of the land from the sea-ward to the land-ward margin 
of the Mount. In short, on the assumptions laid down at the 
commencement, the hypothesis of insulation by mere encroach- 
ment appeared to demand the belief that at least twenty thousand 
years ago Cornwall was inhabited by a people who spoke a lan- 
guage which prevailed in the same district to within a very few 
centuries of our own time, and, from its similarity to the Welsh, 
might be said to be still spoken by a large population within our 
own island. Believing this conclusion respecting the antiquity of 
the old Cornish language to be totally untenable, I at once rejected 
it, and, with it, as a matter of course, the hypothesis of insulation 
by encroachment alone ; remarking of the latter that it squandered 
time most lavishly. 
