Transition rocks

(Geol.) a term formerly applied to the lowest uncrystalline stratified rocks (graywacke) supposed to contain no fossils, and so called because thought to have been formed when the earth was passing from an uninhabitable to a habitable state.

See also: Transition

References in periodicals archive ?
Multiple NNE conductors in Wollaston transition rocks on the property are interpreted as zones of thrusting adjacent to the Archean Key Lake Dome.
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