While placing a bridge over a ravine, a phantom knocked me off the ledge. I fell down approximately 60 blocks and died when I hit the obsidian blocks at the bottom of the ravine. The obsidian blocks were one block thick and there was a lava pool underneath the obsidian. As soon as I died, I heard the hissing noise of items disintegrating in lava. When I returned to retrieve my items, which should have been lying at the bottom of the ravine, they were not there except for my equipped armor and the map I had in my off-hand. All other items were lost, and I assumed they glitched through the layer of obsidian into the lava after the fall. There was no gap in the obsidian that the items could have fallen through into the lava.