"Del Loma Cavern Legends Blasted By Exploration" The Trinity River. N.F. cave explorers found that the main passage of the Del Loma Cove penetrates the mtn. about 300' and there are about 150' of side passages large to admit a man. The largest single room was 20' long by 8'-12' wide + 6'-20' high. hundreds of names and dates were found on the walls, the oldest back to 1849.