Darwin’s Voyage Phase 2, biology homework help

How might the observations that Darwin made at St. Jago and Fernando de Noronha fit in with what he was reading in Lyell’s Principles of Geology?

Resource link for question posed above. Answer should be no less than 3 paragraphs.

http://maps.empire-edutools.net/darwin/atlantic_islands_map.html

http://maps.empire-edutools.net/darwin/south_america_map.html