As the glaciers retreated, the resulting meltwater carved out the Ohio River Valley and exposed the fossil beds.
(the glaciers; retreated; ) (the resulting meltwater; carved out; the Ohio River Valley; T:As the glaciers retreated) (the resulting meltwater; exposed; the fossil beds; T:As the glaciers retreated)
the glaciers the resulting meltwater the resulting meltwater
retreated carved out exposed
the Ohio River Valley T:As the glaciers retreated
the fossil beds T:As the glaciers retreated