Above the Ottauquechee rocks lie those of the _Bethel formation_. Approximately 2,000 feet thick, this formation is composed mainly of pale-green schist with interlaminated thin layers of white to greenish quartzite. The rock presents a distinct banded appearance and contains conspicuous crystals of garnet and the black mica, biotite. The best view of this schist is found along State Highway 100A and slightly over two miles north of the Park entrance road. The relatively steep rock cliffs which line the west side of this road are composed of the resistant Bethel formation. In the northeast portion of Coolidge Forest Park several excellent exposures of this formation in contact with the underlying Ottauquechee formation can be seen, but, to reach these areas you would have to leave the beaten trail. If you are interested in visiting these contact locations it would be best to consult the geologic map for approximate directions. [Illustration: Figure 5. Diagrammatic cross sections illustrating the geologic history of the Calvin Coolidge State Forest Park. Vertical scale greatly exaggerated. Patterns to designate formations in cross section A are repeated in cross sections B and C. A. Horizontal layers of early paleozoic sedimentary rocks were formed. This cross section extends beyond the limits of the Park area. Thicknesses of rock formations are approximately proportional. B. During late Ordovician or Devonian time these sedimentary layers were folded and the rocks metamorphosed. C. Calvin Coolidge State Forest Park as it appears today.] A MISSISQUOI FORMATION BETHEL FORMATION OTTAUQUECHEE FORMATION PINNEY HOLLOW FORMATION B C SHELTER VILLAGE SLACK HILL The conditions under which the Bethel formation was originally deposited are similar to those which existed during Pinney Hollow time. Shale, sandy shale and thin-bedded sandstones formed under shallow water marine conditions; however, restriction with accompanied organic accumulation did not occur. This formation is thought to be of either Cambrian or Ordovician age. The easternmost, and therefore youngest formation to be found in the Park area is known as the _Missisquoi formation_. This formation, which is only partially represented here, is made up of dark phyllite, light blue-gray schist with conspicuous crystals of garnet and biotite, and gray quartzite. The rocks of this formation can be seen along Broad Brook which flows north along the eastern border of Coolidge State Forest Park. This formation is considered Ordovician in age with the conditions of deposition being quite similar to those which existed during Ottauquechee time. Once again the ocean waters were restricted and organic-rich black muds accumulated in quantity on the ocean floor. THE GEOLOGIC HISTORY