320 ON THE ICTIS OF DIODORUS SICULUS. 
communicating with a small creek, or bay, called 
Chair-ladder Cove ; and is supposed to have been 
formed by the decomposition of a portion of the 
rock. On various parts of the cliffs, too, patches 
of disintegrated granite are found, which have 
a sandy, or gravelly appearance, from which it 
may be inferred, that the ocean has made great 
inroads, in the lapse of ages, upon the rocks lying 
along this coast. Nor must it be forgotten, that 
the granite of the Scilly Islands is peculiarly 
liable to decomposition; that portions of these 
islands are rapidly disappearing from this cause 
alone; and that the surface of water which they 
displace is constantly diminishing, although their 
number is increasing, in consequence of their 
being broken up into smaller islets, by the abra- 
ding power of the ocean. 
If, as is generally supposed, the Cassiterides 
of the Greeks were the Scilly Islands, their nun- 
ber in the time of Strabo was only ten.* It is 
now, probably, as many as a hundred and fifty ; 
and it is a singular fact, that they take their name 
of the Scilly Islands from one of their number, 
_which, in its present attenuated state, is nearly 
* Strabonis Res. Geogr. Lib. iii. p. 239. 
