SHALE

Sat, 11 May '24

Burgess ___ (rock bed noted for its fossils)

Thu, 7 Mar '24

Layered rock

Wed, 8 Nov '23

Flaky rock

Fri, 14 Jul '23

Fracking target

Sun, 13 Jun '21

One source of oil

Wed, 31 Mar '21

Thin-layered sedimentary rock