In a hole in the trench there lived a soldier

[Galadriel55]

I totally missed the most obvious one: Mordor landscape.

The gasping pools were chocked with ash and crawling muds, sickly white and gray, as if the mountains had vomited the filth of their entrails upon the lands about. High mounds of crushed and powdered rock, great cones of earth fire-blasted and poison-staines, stood like an obscene graveyard in endless rows...

~The Passage of the Marshes

Indeed the whole surface of the plains of Gorgoroth was pocked with great holes, as if, while it was still a waste of soft mud, it hadbeen smitten with a shower of bolts and huge slingstones. The largest of these holes were rimmed with ridges of broken rock, and broad fissures ran out from them in all directions. It was a land in which it would be possible to creep from hiding to hiding, unseen by all but the most watchfull eyes: possible at least for one who was strong and had no need for speed. For the hungry and worn, who had far to go before life failed, it had an evil look.

~Mount Doom

I think both passages could be describing the landscape of the Somme...