The main formations are pelite metapelites sandstone, and metagraywackes. The first ones show a fine interlocking layering with unclear graded bedding in the sandstone compared to the metapelites, ...

Privately held Birch Resources has made 6.5 MMbbl of oil to date from just 16 wells averaging 15 months old in the Dean sandstone north of Midland, Texas, according to newly public Texas Railroad ...