That is what's left of a WW1 U.S gas mask. It's in pretty rough shape though. U.S.R.C was a designation for ships, "United States Revenue Cutter" They were combined eventually with the Coast Guard. I don't know much about them other than as I remember their primary job was to patrol coastal waters for smugglers. They may have served in some capacity in Europe during the war patrolling the English channel maybe?