Subject ASC0003u5i
The geological magazine, or, Monthly journal of geology.
n.s. decade 4, v. 7 (1900), Page 539 (1900)
Smithsonian Libraries
BHL Page 30762722
Keywords
coal clay Coal fireclay black shale A' coal cross section Fig 1 section of coal and clay-slate Section of Coal and Clay-slate section slate black shale layer bed