Lingula flags of the Lower Silurian system into the Maenturog flags
and slates, the Festiniog flags, and the Dolgelly slates. The
collecting of lepidoptera was his chief amusement in Brazil, where
he made his first acquaintance with the teeming life of the torrid
zone and laid the foundation for those observations on tropical
nature which his longer stay in Nicaragua gave rise to, and which
are recorded in this book.

After his return from Central America, his services were in great
request as a consulting mining engineer, and the succeeding years
of his life were spent in almost continual travel: over all parts of
Great Britain, to North and South Russia, Siberia, the Kirghiz
Steppes, Mexico, and the United States. It was on one of his annual
visits to Colorado that he was seized with sudden sickness and died
on September 21, 1878, at the early age of forty-five.

Thomas Belt was an accurate and intelligent observer possessed of
the valuable faculty of wonder at whatever is new or strange or
beautiful in nature, and the equally valuable habit of seeking a
reason for all he saw. Having found or imagined one, he went on to
make fresh observations, and sought out new facts to see how they
accorded with his supposed cause of the phenomena. "The Naturalist
in Nicaragua" has therefore a value and a charm quite independent
of the particular district it describes. As a mere book of travel
it is surpassed by scores of other works. The country and the
people of Nicaragua are too much like other parts of tropical
Spanish America, with their dull, lazy inhabitants, to possess any
novelty. There is little in the book that can be called adventure,
and still less of geographical discovery.