New South Wales.--Sandstone formation.--Embedded pseudo-fragments of
shale.--Stratification.--Current-cleavage.--Great valleys.--Van Diemen's
Land.--Palaeozoic formation.--Newer formation with volcanic rocks.--
Travertin with leaves of extinct plants.--Elevation of the land.--New
Zealand.--King George's Sound.--Superficial ferruginous beds.--Superficial
calcareous deposits, with casts of branches; its origin from drifted
particles of shells and corals.--Their extent.--Cape of Good Hope.--
Junction of the granite and clay-slate.--Sandstone formation.


INDEX.




GEOLOGICAL OBSERVATIONS ON VOLCANIC ISLANDS.


CRITICAL INTRODUCTION.

The preparation of the series of works published under the general title
"Geology of the Voyage of the 'Beagle'" occupied a great part of Darwin's
time during the ten years that followed his return to England. The second
volume of the series, entitled "Geological Observations on Volcanic
Islands, with Brief Notices on the Geology of Australia and the Cape of
Good Hope," made its appearance in 1844. The materials for this volume were
collected in part during the outward voyage, when the "Beagle" called at
St. Jago in the Cape de Verde Islands, and St. Paul's Rocks, and at
Fernando Noronha, but mainly during the homeward cruise; then it was that
the Galapagos Islands were surveyed, the Low Archipelago passed through,