Downtonian Stage

(also, Downtonian series or Downton. from the name of Downton Castle in Shropshire, Great Britain), a lower subdivision of the Old Red Sandstone of the Devonian system of Great Britain. This stage was identified by C. Lapworth in 1879 and was originally considered the upper (fourth) stage of the Silurian system. In stratotype it is composed at its base of fossil-bearing breccia, higher it is composed of sandstones, siltstone, and argillites, and in the upper half of its cross section it is composed of red marls. The Downtonian stage contains the remains of fish, os-tracods, lingulids, and in the lower part also conodonts and articulate brachiopods. This stage exists in southern Wales and in Scotland and Ireland. A precise comparison of the Downtonian with marine sections of the lower Devonian in Western Europe has not yet been carried out. and for this reason it is considered a series, or regional stratigraphic subdivision.there.