The Source by Michael Cordy — and a lack of geology

The Source by Michael Cordy is not, I suspect, my type of book, being a historical adventure crime thriller of the religious "Indiana code" variety (this time to do with the Garden of Eden rather than the Ark or the descendants of Christ). However, I was taken with Michelle Peckham's review on Euro Crime (she recommends the book), and this part in particular:

The main character, Ross Kelly is apparently a geologist, and I thought this might have been used to more effect as they searched for and then reached the garden. But his skills in reading rocks and geological formations were not really used in his quest.

It seems a wasted opportunity, to write a book about a lost archaelogical artefact, featuring a geologist, and not have these scientific skills involved in the solution to the mystery, or otherwise be critically useful. Surely a specialist knowledge of the type of rock at a crucial moment in the plot, or a convenient hammer kept strapped to the ankle underneath the trousers, could have been worked in? Sedimentary, my dear Watson.