As scientists collected fossils from different rock layers and formations, they discovered that they could often recognize the rock layer by the assemblage of fossils it contained.
(scientists; collected; fossils; from different rock layers and formations) (fossils; contained; it) (they; discovered; that they could often recognize the rock layer by the assemblage of fossils; T:As scientists collected fossils from different rock layers and formations) Context(they discovered,List([75, 90))):(they; could recognize; the rock layer by the assemblage of fossils; T:often)
they discovered,List([75, 90))
scientists fossils they they
collected contained discovered could recognize
fossils from different rock layers and formations
it
that they could often recognize the rock layer by the assemblage of fossils T:As scientists collected fossils from different rock layers and formations
the rock layer by the assemblage of fossils T:often