Named for community of Nasons, Orange Co., central VA. These rocks were informally designated unnamed Cambrian quartzite by Pavlides (1989) and subsequently changed to unnamed quartzite-siltstone granule conglomerate by Pavlides (1990). Occurs as a lenticular formation. In type area, consists of pea-sized granule quartz conglomerate but locally grades to finer and coarser grain sizes. Where it wedges out to the northwest, approx 2.1 km northeast of Nasons, granule quartz conglomerate is minor lithology. Granule conglomerate is successively overlain to the southeast by quartz meta-arenite (quartzite) and then siltstone. Thickness ranges from 0 to as much as 125 m. Contacts with enclosing rocks not exposed; may locally unconformably overlie Late Proterozoic Catoctin Formation and Late Proterozoic(?) or Cambrian(?) Tomahawk Creek Formation (new) and is in turn unconformably overlain by True Blue Formation (new). Considered to be in part correlative with part of Weverton Formation and basal part of the Chilhowee Group, exposed elsewhere along flanks of Blue Ridge anticlinorium. Provisionally assigned a Cambrian age. Report includes geologic map and correlation chart.

Source: GNU records (USGS DDS-6; Reston GNULEX).