Note {322} — Chapter IV · ON THE NUMBER OF INTERMEDIATE FORMS REQUIRED ON THE THEORY OF COMMON DESCENT; AND ON THEIR ABSENCE IN A FOSSIL STATE
Reading edition
See Origin, Ed. i. p. 310, vi. p. 452 for Lyell's metaphor. I am indebted to Prof. Judd for pointing out that Darwin’s version of the metaphor is founded on the first edition of Lyell’s Principles, vol. I. and vol. III.; see the Essay of 1842, p. 27.