Foraminifers from the upper part of the Lewis Shale (Upper Cretaceous) near Durango, Colorado

Subsurface Analysis of the Mesaverde Group on and near the Jicarilla Apache Indian Reservation, New Mexico-its implication on Sites of Oil and Gas Accumulation

“…3). The upper 327 ft (99 m) of the Lewis below the Pictured Cliffs in the northern part of the basin has yielded mostly arenaceous benthic foraminifera (Carey, 1990) suggesting much shallower, nearshore environments for much of the upper Lewis. These data support the generally regressive nature for most of the Pictured Cliffs-Lewis couplet in the northern part of the basin.…”