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Monday [4 April 1836]

Crossed over to West Isld. — Found on one part of Beach, exposed beds of Calc Sandstone precisely resembling those of Horsburgh Isd.: Here then the Lagoon eats its own formations: I several other places old trees have been undermined & fallen:

In another part, a large lagoon covered with the finest white sand, is only covered at Spring tides;

It is formed of spits of bits of branched Coral thrown up by gales of wind, into which the tides carry very fine sand, no doubt in these parts the general action is to add to the land Where I have seen such addition is off Horsburgh & West Isd: at SE Isd. there was shoal but no addition. & in the whole upper part of lagoon. — On outer coast, which is the Leeward coast, the reef is very broard; the Breccia slopes down to it, is only covered by very few loose fragments or by a sand beach — This is evidently owing to flat having totally destroyed the effect of breakers. — There is however in part a little way inland, a high beach & some sand hillocks. — That the surf once broke here is certain; because in an oblique line, (from the curl of the windward swell) on a point there are heavy breakers, on the shore in this line is the thickest & largest mass of Breccia I have ever seen, stratified in a curve conformably to the coast — Ancient trees grow on the few lone trees stones on the Breccia, & indeed in a great part of this coast, the sea is rather removing the loose sand covering & trees above the Breccia, small subsidence:

This is another half sheet of the "W. FINCHER 1835" paper; not an apparent mate of CUL-DAR41.46. Page written in pencil.

Where I have seen such addition is off Horsburgh ... addition.] ink.

48v

The reef here is precisely similar to Tahiti¹only rather higher, covered & superficially composed of the three species of Corallina (the pretty species I saw no where else). — (Mem. how strange it is Corallina, although tidal flourish only in the Breakers & a little (but I suspect a different species) in the lagoon). About 3 inches beneath the general level of the [live] Corallina, the breakwater is excessively hard, by chissel, pixaxe & I at last attained a fragment & strongly suspect it is Corallina ([blank]) petrified

Different circumstances determine waste & petrifaction

Everywhere I hear of water pumping over the reefs.

The lateral advance of Coral is certain. from the state of this reef. —

The slope of reef is to the Isld, in these distant reefs — the growing part being highest. —

The great inequality here subsidence. —

The strip of outside land is here narrow. but exists in full character: — Tahiti excellent description. Corallina on the Breakwater. chiefly the sub-branched kinds —

Few fragments on this reef. — sea no powers: this perhaps is cause of width of reef: not having made a beach & Breccia.

Sounding irregular. according to Manner & rapidity of depressions. —

Sand in lagoon not cemented.

¹ Darwin uses Tahiti, rather than Otaheite.

The reef here ... three species of Corallina] pencil.

(the pretty species I saw no where else).] inl.

— (Mem. how strange ... sea no powers] pencil.

this perhaps is cause ... beach & Breccia.] ink.

Sounding irregular. ... not cemented.] pencil.