Origin of graywacke
Words nearby graywacke
How to use graywacke in a sentence
Appropriately pronounced a "secondary graywacke slate," by Mr. Eaton.
In the transition graywacke of the south of Scotland, the galena mines of Leadhills occur.A Dictionary of Arts, Manufactures and Mines|Andrew Ure
Their material, however, is not flint, but either graywacke or a kind of tough slate.North American Stone Implements|Charles Rau
Is it primitive, or is it graywacke like Catskill Mountains?
I received a specimen of slaty graywacke from Lake Superior.