A mystery solved.

The glacier was God's great plough set at work ages ago to grind, furrow, and knead over, as it were, the surface of the earth.
Louis Agassiz. Swiss biologist and geologist. 1807-1873


A couple of years ago I was rooting around in a local ice-age kame, a mound of sand, gravel and till left behind by a retreating glacier. I was hoping for some ancient shells but found none. What I did find was this object. It is about 10 cm in length and consists of a core of highly compacted, coarse greenish-yellow sediment encased in a hard "skin" which is flaking off.


At the time, I had no idea as to what it was. Yesterday, flipping through The Hamlyn Guide to Minerals, Rocks and Fossils I finally managed to identify it as Aelolian clay (loess). Aeolian clays are derived from fine glacial material deposited by the wind.