Boulder clay is stony clay left behind by melting ice. Dig through boulder clay.
The stones in it come from wherever the ice travelled, sometimes hundreds of miles. Boulder clay makes heavy farmland and is why so much of eastern England grows wheat.
1nounboulder clayStony clay left behind by melting ice.
“The trench went through two metres of boulder clay.”
boulder clay is a soil.
Practised in Rocks & Minerals