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APPENDIX. 
poritic island of Medinilla), and appear to be without 
reefs. — Mangs, however, is described (by Freycinet, p. 219, 
Hydrog.) from some Spanish charts, as formed of small 
islands placed ‘ au milieu de nombreux recifs ; ’ and as 
these reefs in the general chart of the group do not project 
so much as a mile ; and as there is no appearance from a 
double line, of the existence of deep water within, I have 
ventured, although with much hesitation, to colour them 
red. Respecting Folger and Marshall Islands, which lie 
some way east of the Marianas, I can find out nothing, 
excepting that they are probably low. Krusenstem says 
this of Marshall Island ; and Folger Island is written with 
small letters in D’Urville’s chart ; uncoloured. 
Bonin or Arzobispo Group. — Peel Island has been 
examined by Captain Beechey, to whose kindness I am 
much indebted for giving me information regarding it : ‘at 
Port Lloyd there is a great deal of coral ; and the inner 
harbour is entirely formed by coral-reefs, which extend 
outside the port along the coast.’ Captain Beechey, in 
another part of his letter to me, alludes to the reefs fring- 
ing the island in all directions ; but at the same time it 
must be observed that the surf washes the volcanic rocks 
of the coast in the greater part of its circumference. This 
island has certainly been elevated at least 50 feet within 
the recent period (see Journal of Geolog. Soc. 1855, p. 
532). I do not know whether the other islands of the 
archipelago are fringed ; I have coloured Peel island red. 
— Grampus Island, to the eastward, does not appear 
(Meare’s Voyage, p. 95) to have any reefs, nor does 
Rosario Island (from Lutke’s chart), which lies to the 
westward. Respecting the few other islands in this part 
of the sea, namely the Sulphur Islands, with an active 
volcano, and those lying between Bonin and Japan (situated 
near the extreme limit in latitude at which reefs can grow), 
I have not been able to find any clear account. 
