geological-time

Unkar Delta at Mile 73The layers of brick red sandstone, siltstone, and mudstone of the Dox formation deposited a billion years ago, erode easily, giving the landscape an open, rolling character very different that the narrow, limestone walled canyon upstream, both in lithology and color, fully fitting Van Dyke__ description of __aspberry-red color, tempered with a what-not of mauve, heliotrope, and violet._ Sediments flowing in from the west formed deltas, floodplains, and tidal flats, which indurated into these fine-grained sedimentary rocks thinly laid deposits of a restful sea, lined with shadows as precise as the staves of a musical score, ribboned layers, an elegant alteration of quiet siltings and delicious lappings, crinkled water compressed, solidified, lithified.