When I first began the novel, I had a different prologue. My first plot point thought was--in this newly expanding era of technology (remember the novel takes place in 1993 -- the iPhone was just a dream of Jobs) -- where would a bad guy hide important information that would remain protected and untraceable? Well, when I thought about the clearing and finding the coin, I also used another element of the region -- the oratoires.
Oratoires are found EVERYWHERE in the hiking trails of France, around the roads, and in the middle of nowhere, actually. They are usually built of pierre seche (no cement used) and are erected to place a saint, or usually the Virgin Mary, in the small niche. This is used by the farmers of the region to give thanks for a good harvest, or by anyone who wanders the place who wants to say prayers of protection on their travels. Sometimes they were erected as stopping points in pilgrimages to also give thanks to the saint protecting the region. When traveling the region, I found quite a few of these and used it for my original prologue. And although I changed the prologue completely, I kept this plot point.