2 examples of felstone in sentences

But to return, let us take, as an example, a sample of these boulder clay pebbles from the neighbourhood of Liverpool and Birkenhead, made by Mr. De Rance, the government geological surveyor: Granite, greenstone, felspar porphyry, felstone, quartz rock (all igneous rocks, that is, either formed by, or altered by volcanic heat, and almost all found in the Lake mountains), 37 per cent.

Suppose that hardened in long ages (as it would be under pressure) into a bed of fine grained Felstone, or volcanic ash; and we can understand how the ash-beds of Snowdoniawhich may be traced some of them for many square miles were laid down at the bottom of an ancient sea.

2 examples of  felstone  in sentences