I just thought I would post some pics of the 'Pocket' area of Red Beach One showing one of the last positions to fall. There was a huge sand covered concrete blockhouse near the beach at the deepest part of the reentrant. I've seen film of the backside - I guess the entry portals - before but just noticed what it really was in the larger over-flight photo of Black Beach One. I am also posting what I believe to be that concrete blockhouse as it appeared long after the battle. Here are the pics.
Note the upper left corner and the three darker openings in the sand in both the close up pic and the over-flight photo.
Just thought I'd share my continued research of the battle.