[See here for all my posts on Pattrick Matthew and plagiarism claims made on his behalf.]
[update: 6 jan. 2015] Added one ruby at page 373.
The following is a graphic illustration of the structure of On Naval Timber and Arboriculture by Patrick Matthew (1831). The number line is proportional to the pages of the book. Particular pages are marked. For example, the Introduction goes from page 1 to page 5. The title page, preface etc. all come before page 1.
As can be seen from this illustration, the biggest part of the book is Part IV, which is a critique of previous works of other scholars that have treated arboriculture. This is the biggest heap of rubbish, so to speak, but it also contains one of the most significant rubies, the one containing the phrase "natural process of selection."
For more information on the structure and contents of the book see this previous post.