I don't know the English term for the lava formation we see here. If you are heading towards Búrfellsgjá there is an even bigger one coming up. In Icelandic these are called Hraunhvolf, which translates to Lava Dome. Beautiful.
As with all my caches, I appreciate help with maintenance. If the cache is missing from its obvious spot, feel free to replace it. If the log is wet or full, feel free to throw it away and replace it with any piece of paper you may have in your pocket :)