-on sphaerulites.

seale, mr., geognosy of st.helena.

-on dikes.

-on embedded birds' bones.

seale, on extinct shells of st.helena.

sedgwick, professor, on concretions.

septaria, in concretions in tuff.

serpulae on upraised rocks.

seychelles.

shells, colour of, affected by light.

-from van diemen's land.

-land, extinct, at st.helena.

-particles of, drifted by the wind at st.helena.

shelly matter deposited by the waves.

siau, m., on ripples.

signal post hill.

silica, deposited by steam.

-large proportion of, in obsidian.

-specific gravity of.

siliceous sinter.

smith, dr.a., on junction of granite and clay-slate.

spallanzani on decomposed trachyte.

specific gravity of recent calcareous rocks and of limestone.

-of lavas.

sphaerulites in glass and in silicified wood.

-in obsidian.

sowerby, mr.g.b., on fossil-shells from van diemen's land.

-from st.jago.

-land-shells from st.helena.

st.helena.

-crater of elevation of.

st.jago, crater of elevation of.

-effects of calcareous matter on lava.

st.paul's rocks.

stokes, mr., collections of sphaerulites and of obsidians.

stony-top, little.

-great.

stratification of sandstone in new south wales.

streams of obsidian.