Probably named for Calderwood's [Calderwood] Neck on Vinal Haven [Vinalhaven] Island, Knox Co., south-central coastal ME. Consists of dark quartzitic slates, banded schists (quartzose but varying in color and grain), and quite massive quartzites occurring on northeast part of the island. Felsitic rocks occur in close proximity to the granite and volcanic rocks and undoubtedly represent contact phases of Calderwood's Neck series. These are mottled or variegated, generally a light green. Age is probably older than Niagara.

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

Name revised as Calderwood formation. Applied to all rocks described and mapped by Smith (1896) as Calderwood's Neck schists. Probably belongs to either the Islesboro or Penobscot formations, but its isolated position prevents certain correlation. Age is Cambrian(?).

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

In this paper, the Calderwood is correlated with the Cranberry Island Series of Shaler (1889). The name Cranberry Island is used throughout the paper. Rb/Sr whole-rock isochron on the Cranberry is 387+/-9 Ma, which translates into Devonian age. Calcite-bearing samples can yield erroneous data, however; for instance, a calcite-bearing sample of Cranberry yielded a 368+/-33 Ma date.

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