In the Rio de Oro area there is a considerable amount of interbedded and interlaminated
gray and dark-gray argillaceous very fine- to fine-grained sandstone, the beds ranging from 0.
ice-proximal glacimarine sediments in Muir Inlet, Alaska.
Residual bauxites developed in the weathering, interlaminated
, carbonate rocks, schists, and metasomatic rocks of Rifean age.
The brief description in the map legend indicates a lithology consisting of interbedded to interlaminated
, pale yellow sand with common siderite concretions and nodules.
and occurs within or upon cyclically interlaminated
to interbedded, thin, horizontally laminated, very-fine or fine-grained grey sandstones and dark grey siltstones.
The specimens range up to 40 x 40 cm in size, with smooth to crusty surfaces, and interlaminated
chrysocolla/heterogenite matrix typical of the Shaba localities.
Rhyolite of the Porten Road Formation continues for another 100 m downstream and is followed after a gap of 50 m by greyish green silty mudstone interlaminated
with fine-grained, greyish brown sandstone inferred to again represent the lower part of the Eel River Formation.