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

Much glacial boulder clay covers all the higher ground of the county; it is a stiff brownish clay with many chalk fragments of travelled rocks.

From Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 1 "Calhoun" to "Camoens" by Various

Glacial boulder clay lies over much of the lower ground, and ridges of gravel and sand flank the hills and form extensive sheets.

From Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 7 "Gyantse" to "Hallel" by Various

Lyell visited Kinnordy from time to time between 1817 and 1824, and found on his father's estate and other localities in Strathmore a number of small lakes, lying in hollows of the boulder clay.

From The Coming of Evolution The Story of a Great Revolution in Science by John W.

The more usual arrangement is boulder clay overlain by modified drift, the first being laid down by the ice itself, the second being deposited by streams from the melting glacier in its retreat.

From Drainage Modifications and Glaciation in the Danbury Region Connecticut State of Connecticut State Geological and Natural History Survey Bulletin No. 30 by Sawyer-Harvey, Ruth