'2 The American Geologist. January, 1896 
The study of these broader aspects of geological history 
was taken up early in life and continued almosl withoul in- 
terruption. Previous to L850 appeared articles on "The areas 
of subsidence in the Pacific, as indicated by the distribution 
of coral islands," "The volcanoes of the moon," "The origin 
of continents," "Geological results of the earth's contraction 
in consequence of cooling," and "Origin of the grand outline 
features of the earth." About forty papers on the same or 
kindred topics appeared after L850, and give farther emphasis 
to this genera] character of his geological studies. Even in 
the last five years of his life, and forty years after the publi- 
cation of the papers above cited, we find him still progressive 
and active along the same lines of thought, and writing on 
"The origin of the deep troughs of the oceanic depression. 
Are any of volcanic origin?," "Characteristics of volcanoes, 
with contributions of facts and principles from the Hawaiian 
islands," "Archaean axes of eastern North America," "Rocky 
Mountain protaxis and the post-Cretaceous mountain making 
along its course.*' "The genesis of the heavens and the earth 
and all the host of them. 1 * "Features of non-volcanic igneous 
ejections as illustrated in the four rocks of the New Haven 
region," and "On New England and the Upper Mississippi 
basin in the < Jdacial period." 
It is not difficult to explain this broad scope of subjects, for 
it is undoubtedly due to his early personal familiarity with 
most of the prominent features of the earth's surface. Even 
before graduation from college, he made a cruise through the 
.Mediterranean, visiting the seaports of France, Italy, Greece, 
and Turkey. Five years later, in L838, he was appointed min- 
eralogist and geologist to the United States Exploring Expedi- 
tion under Wilkes and for four years travelled extensively, 
for the most part in the southern hemisphere. The expedi- 
tion visited both coasts of South America, many of the is- 
lands of the South Pacific, Australia, New Zealand, thence 
north to the Gilbert archipelago, the Caroline islands, the 
Sandwich islands, and the coasl of Oregon. Hereafter suffer- 
ing shipwreck and the loss of personal property and some of 
the collections, he travelled overland to San Francisco. The 
return to New York was by way of the Sandwich islands. Sing- 
apore, the Cape of Good Hope, and St. Helena. 
