Fine-grained sedimentary rock formed from hardened clay and silt that lacks the thin layers typical of shale .
(Fine-grained sedimentary rock; formed; from hardened clay and silt) (hardened clay and silt; lacks; the thin layers typical of shale)
Fine-grained sedimentary rock hardened clay and silt
formed lacks
from hardened clay and silt
the thin layers typical of shale