硬砂岩 meaning in English

blaize
clasmoschist
grauwacke
graywacke
greywacke
hard sandstone
hd.sd

Limestone , gypsum , basalt , dolomite , granite , greywacke
石灰石石膏玄武岩白云石花岗岩硬砂岩
He was deeply impressed to see the workers breaking large bars out of steep walls of rock and filling the valley with thunder . greywacke becoming gravel through massive hammer strokes
当时，工人们震天动地从岩壁上取下巨石以及用锤把硬砂岩敲打成碎石的情景给他留下深刻的印象。