346 Darwin and Geology 
certainly have done) “on no account to accept the views therein 
advocated.” It is probable that the days of waiting, discomfort 
and sea-sickness at the beginning of the voyage were relieved by the 
reading of this volume. For he says that when he landed, three 
weeks after setting sail from Plymouth, in St Jago, the largest of the 
Cape de Verde Islands, the volume had already been “ studied 
attentively; and the book was of the highest service to me in many 
ways....” His first original geological work, he declares, “ showed me 
clearly the wonderful superiority of Lyell’s manner of treating 
geology, compared with that of any other author, whose works I had 
with me or ever afterwards read®.” 
At St Jago Darwin first experienced the joy of making new 
discoveries, and his delight was unbounded. Writing to his father 
he says, “Geologising in a volcanic country is most delightful ; 
besides the interest attached to itself, it leads you into most beautiful 
and retired spots*.” To Henslow he wrote of St Jago: “Here we 
spent three most delightful weeks....St Jago is singularly barren, 
and produces few plants or insects, so that my hammer was my 
usual companion, and in its company most delightful hours I spent.” 
“The geology was pre-eminently interesting, and I believe quite 
new; there are some facts on a large scale of upraised coast (which 
is an excellent epoch for all the volcanic rocks to date from), that 
would interest Mr Lyell.” After more than forty years the memory 
of this, his first geological work, seems as fresh as ever, and he wrote 
in 1876, “The geology of St Jago is very striking, yet simple: a 
stream of lava formerly flowed over the bed of the sea, formed of 
triturated recent shells and corals, which it has baked into a hard 
white rock. Since then the whole island has been upheaved. But 
the line of white rock revealed to me a new and important fact, 
namely, that there had been afterwards subsidence round the craters, 
which had since been in action, and had poured forth lava®.” 
It was at this time, probably, that Darwin made his first attempt 
at drawing a sketch-map and section to illustrate the observations he 
had made (see his Volcanic Islands, pp. 1 and 9). His first im- 
portant geological discovery, that of the subsidence of strata around 
volcanic vents (which has since been confirmed by Mr Heaphy in 
New Zealand and other authors) awakened an intense enthusiasm, 
and he writes: “It then first dawned on me that I might perhaps 
write a book on the geology of the various countries visited, and 
this made me thrill with delight. That was a memorable hour to me, 
and how distinctly I can call to mind the low cliff of lava beneath 
which I rested, with the sun glaring hot, a few strange desert 
1 ZL. 2.1. p. 73. 21. L.1 p. 62. 3 L.L. 1, p. 228. 
4.1L. Lt. p. 235. 6 L.L.1p. 65. 
