Linked from
The 10 pages that link to Shale, each with the reason it gives.
Sedimentary rockBroader topic: Its mud-sized particles commonly settle in quiet water.
SlateRelated: Shale is a common precursor whose minerals realign during slate formation.
FlyschRelated: Quiet intervals between flow events often leave mud that later becomes shale.
SiltstoneCompared with: Siltstone can resemble shale, but shale's fissility is a defining texture.
Clastic rockBroader topic: Shale commonly forms from compacted clay- and silt-rich clastic sediment.