ABSTRACT. J. D. Dana was a pioneering American naturalist who
put an impressive stamp on four fields-mineralogy, zoology, volcanology,
and geology-during a long career. Educated at Yale, the seminal
event of his post-graduate education was participation in the
United States Exploring Expedition in the Pacific between 1838
and 1842. Observations of atolls, volcanic islands, and active
Hawaiian volcanoes, together with insights gained from the charting
activities of the expedition, enabled him to make the first synthesis
of volcanic action in the Pacific and to formulate the broader
doctrines of the contrasts between, and the permanence of, continents
and ocean basins, and of the historicity of the Earth.
The magnitude of Dana's contribution must be viewed from the perspective
of geological sciences in the early 19th century. At the onset
of the Exploring Expedition, direct accounts of volcanic action
were scant, the Wernerian neptunist view of the aqueous origin
of basalt had only just been laid to rest, most geologists still
had no clear conception of how basalts erupted from volcanoes,
fossil sequences were only beginning to be understood, and both
geological mapping and systematic stratigraphy were in their infancy.
Dana had little formal training in geology, but his observational
skills were already evident in an early description of flowing
lava and fire fountaining at Vesuvius (1835). Wide reading had
made him familiar with current concepts of continental geologists.
Dana was perhaps the first trained naturalist to observe the fluida1
character of erupting basaltic lava, this at Kilauea on Hawaii,
and he at once understood how this contrasted with the more viscid
attributes of lava at Vesuvius. But he was also able to perceive
how basaltic eruptions could build a large volcanic island, and
to understand that fluvial action and subsidence eventually could
reduce a Hawaii to an eroded volcanic stub, sustained as a land
area only by the countergrowth of fringing and barrier reefs.
Dana identified the linear arrangements of volcanic chains on
the sea floor and established their age progressions using extent
of erosion and development of offshore reefs. He predicted the
existence of the vast tracts of drowned and deeply submerged atolls,
now termed guyots, in the western Pacific, and said where they
could be found.
Dana the geologist was unreservedly historical, a perspective
that reflected his Christian opinion of the human estate as the
culmination of Divine creation. The geological past was directed
toward this moment no less than recorded human history, with a
genuine beginning and substantive changes through time. This view
contrasted with the uniformitarian (deistic] opinions of Hutton
and especially Lyell, who saw processes repeated through an indeterminant
length of time but no pattern of fundamental change. Dana's North
American puritan tradition gave him the optimism that an Earth
history could be established by human ingenuity and effort, and
it persuaded him to devote all his energies to this end. Dana
entered the Pacific seeking broad patterns. The first of these
he discerned was the interaction of volcanic action, fluvial erosion,
subsidence, and coral growth on the islands he explored, leading
to formation of atolls. This provided proof of direction in Earth
history and a unifying planetary perspective, focused on volcanology,
which was first outlined in Dana's report on Geology for the Exploring
Expedition in 1849. Later, through voluminous writing and years
of teaching, Dana carried these views to a position of extraordinary
influence and importance for all subsequent geological science.