- any one of different dark gray sandstones that have shale.
- Alternative as a type of greywacke.
- A conglomerate or grit stone, composed of curved pebbles and sand firmly united together.
- In geology, a concise aggregate of curved or subangular grains of various silicious rocks, held collectively by a paste that is generally silicious.
Sentence for "graywacke"
- Ecoregion 66c is underlain by Precambrian…
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