TABLE 1: Formations of the Casco Bay Group
| Formation | Description |
|---|
| Jewell Formation |
Rusty and non-rusty weathering mica-rich schist and phyllite. |
| Spurwink Formation |
Thinly bedded gray metalimestone and phyllite. |
| Scarboro Formation |
Rusty and non-rusty weathering mica-rich schist and phyllite with minor thin-bedded limestone. |
| Diamond Island Formation |
Coal-black rusty-weathering phyllite composed of quartz, white mica (muscovite), graphite, and pyrite. |
| Spring Point Formation |
Typically greenish gray amphibolite-chlorite schist; minor quartz-feldspar-mica gneiss. |
| Cape Elizabeth Formation |
Thinly bedded light gray to slightly reddish brown weathering impure quartzite and dark gray phyllite. |
| Cushing Formation |
Predominantly feldspar-quartz-biotite gneiss; minor amphibolite and rusty-weathering gneiss with abundant garnet. |
Last updated on January 16, 2008
