Glacial erratic boulder on stilts, Norber
A huge glacial erratic boulder of greywacke ('Millstone Grit') perched on a few remaining 'stilts' of un-eroded limestone. Norber boulder field above Austwick, North Yorkshire.
Glacial erratic boulders were transported sometimes great distances by a glacier during the last Ice Age and deposited on top of the very different local rock as the ice sheet started to melt. As such, they stand out as alien to the surrounding landscape and they serve as reminders of the sheer power of glaciers.
On Norber, much of the local limestone rock has been eroded away, but a little survives under the protection of the much harder greywacke boulders where it acts as a pedestal or - more spectacularly - as individual stilts or legs as seen here.
Date taken: 05 May 2013.