graywacke

graywacke is defined in Webster's Unabridged Dictionary (1913) with 1 sense. The full text of each entry is reproduced verbatim below.

Definitions

  1. 1.A conglomerate or grit rock, consisting of rounded pebbles sand firmly united together. Note: This term, derved from the grauwacke of German miners, was formerly applied in geology to different grits and slates of the Silurian series; but it is now seldom used.

Source: Webster's Unabridged Dictionary, 1913 edition (public domain, via GCIDE / Project Gutenberg).

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