t) has appeared in an address to the Geological Society in
1890; and many discoveries, like that of Dr Woolnough in Fiji, have
led to considerable qualifications of the generalisation that all the
islands in the great ocean are wholly of volcanic or coral origin.

I remember once expressing surprise to Darwin that, after the views
which he had originated concerning the existence of areas of elevation
and others of subsidence in the Pacific Ocean, and in face of the
admitted difficulty of accounting for the distribution of certain
terrestrial animals and plants, if the land and sea areas had been
permanent in position, he still maintained that theory. Looking at me
with a whimsical smile, he said: "I have seen many of my old friends
make fools of themselves, by putting forward new theoretical views or
revising old ones, AFTER THEY WERE SIXTY YEARS OF AGE; so, long ago,
I determined that on reaching that age I would write nothing more of a
speculative character."

Though Darwin's letters and conversations on geology during these later
years were the chief manifestations of the interest he preserved in his
"old love," as he continued to call it, yet in the sunset of that active
life a gleam of the old enthusiasm for geology broke forth once more.
There can be no doubt that Darwin's inability to occupy himself with
field-work proved an insuperable difficulty to any attempt on his part
to resume active geological research. But, as is shown by the series of
charming volumes on plant-life, Darwin had found compensation in making
patient and persevering experiment take the place of enterprising and
exact observation; and there was one direction in which he could indulge
the "old love" by employment of the new faculty.

We have seen that the earliest memoir written by Darwin, which was
published in full, was a paper "On the Formation of Mould" which was
read at the Geological Society on November 1st, 1837, but did not appear
in the "Transactions" of the Society till 1840, where it occupied four
and a half quarto pages, including some supplementary matter, obtained
later, and a woodcut. This little paper was confined to observations
made in his uncle's fields in Staffordshire, where burnt clay, cinders,
and sand were found to be buried under a layer of black earth, evidently
brought from below by earthworms, and to a recital of similar facts from
Scotland obtained through the agency of Lyell. The subsequent history
of Darwin's