Sam Rowe Ridge Formation (new name), part of the Prentiss Group (new) is composed mostly of medium gray sandstones, siltstones, and non-carbonaceous slates. Also locally contains conglomerate horizons and a few beds of volcanic rock. Pelite tops of graded beds are commonly burrowed. Overlies Mill Priviledge Brook Formation (new) and underlies (ascending) Ellen Wood Ridge Formation (new) and Daggett Ridge Formation (revised), all of Prentiss Group. Probably Silurian, but here conservatively assigned an Ordovician to Silurian age.

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

Post-Caradocian Miramichi rocks may be divided into four formations. All four (Daggett Ridge, Mill Priveledge Brook, Sam Rowe Ridge, and Ellen Wood Ridge Formations) appear to interfinger. Sam Rowe Ridge is named for numerous fairly large pavement exposures of interbedded gray pelite and feldspathic wacke found in clearcuts and roadbeds in the vicinity of Sam Rowe Ridge in Prentiss Plantation. Appears to be thickest in this area and thins to the north and south. Rocks are distinguished from underlying Mill Priveledge Brook by the color of the pelitic beds, which are medium gray or light bluish gray and by the color of the wackes, which weather to a light gray or buff, reflecting higher feldspar content. Pyrite is rare and ankerite is the dominant iron mineral. Sandstone beds are regular and continuous. Minor lithologies include conglomerate, argillaceous limestone, and volcanic rock. Interfingers to the west with the lower part of the Smyrna Mills Formation.

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