boulder clay

American  

noun

Geology.

1. a glacial deposit consisting chiefly of unstratified clay with embedded boulders.

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boulder clay British  

noun

1. an unstratified glacial deposit consisting of fine clay, boulders, and pebbles See also till 4

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Etymology

Origin of boulder clay

First recorded in 1855–60

Example Sentences

Happisburgh, home to about 1,100 people, is so susceptible to erosion because the cliffs are made from boulder clay which slumps when wet.

From BBC • Dec. 30, 2022

It is not clear, but black with mud, called boulder clay, or till, made of ground rock, and mixed with fragments of all shapes and sizes.

From Earth and Sky Every Child Should Know Easy studies of the earth and the stars for any time and place by Rogers, Julia Ellen

In the regions of the country where the drift soil, left by the great ice-sheet, lies deepest, the glacial boulder clay is very far down.

From Earth and Sky Every Child Should Know Easy studies of the earth and the stars for any time and place by Rogers, Julia Ellen

The largest transported mass occurs at Linksfield, where a succession of limestones and shales rests on boulder clay and is covered by it, which from the fossils may be of Rhaetic or Lower Lias age.

From Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" by Various

The glacier that lodged it there, also rounded the granite dome in Central Park and scattered the rock-strewn boulder clay on Long Island.

From Earth and Sky Every Child Should Know Easy studies of the earth and the stars for any time and place by Rogers, Julia Ellen