Named the Lurich formation for Lurich, Giles Co., VA. Consists of calcilutite of variable thickness that passes down into beds containing nodular black chert and beds of chert-pebble conglomerate in dolomite. The Lurich can be divided into (ascending) the Blackford member (chert-pebble conglomerate and dolomite), Elway member (DINORTHIS-bearing calcilutite with black chert nodules), and Five Oaks member (calcilutite). Thickness is approximately 300 feet. Unit overlies the Canadian series and underlies the Lincolnshire limestone. The Lurich formation is of Middle Ordovician (Chazyan) age.

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

The Lurich formation in VA can be divided into a lower basal clastic unit and an upper Five Oaks member. The basal clastic unit consists of 169 feet of dark gray and olive gray, fine- to very fine-grained, thin- to medium-bedded limestone with limestone conglomerate, shaly interbeds, and black chert; unit is equivalent to the Blackford and Elway members of Kay (1956). The Five Oaks member consists of 116 feet of olive gray and medium gray, aphanitic, thin- to medium-bedded limestone or calcilutite. The Lurich overlies the Beekmantown formation and underlies the Lincolnshire limestone. Unit is of early Middle Ordovician age.

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