Code Talker by Joseph Bruchac

The next two days on Cape Torokina were spent setting up our base and strengthening our position while small parties tried to follow the trails that led farther into the island. It wasn't easy. The jungle was thick and the trails dangerous and narrow. Everything about Bougainville was strange to me. As a Navajo, I was used to a dry land and so were most of the other Marines. Unlike our enemies, our men had never fought in this kind of terrain before.

I quickly discovered that the whole island, aside from the first hundred yards nearest the beach, was nothing but swampy jungle. Whenever I dug another foxhole, cutting down through ferns and rotted vegetation and tree roots and mud, the bottom of it would be filled with water by the time I finished. Whatever wasn't jungle was steep and rugged hills. There was even a volcano on that island and while I was there it was erupting!