Most of the sand now found north of the Park bathing beach and which is responsible for the extensive “shallows” in the swimming area, was supplied by the now abandoned northern channel of the Lamoille River. It is interesting to note that most of the sand now seen on the bathing beach has been imported from nearby areas of Vermont. Since the northern distributary channel of the Lamoille River is no longer supplying sand, and sand from the active southern channel cannot work its way northward because of the Sand Bar Bridge causeway, there is a lack of sand for the beach.
The extensive swamp areas near the east end of Sand Bar Bridge are a wildlife sanctuary. The north-trending prominent escarpment east of the Park marks the trace of the Champlain thrust fault ([Fig. 13]). In a quarry at the east end of Sand Bar Bridge may be seen the fault contact between the younger, Middle Ordovician, Stony Point Formation, and the older, Lower Cambrian, Dunham Dolomite.
SUGGESTED READING
Erwin, R. B., 1957, The Geology of the Limestone of Isle La Motte and South Hero Island, Vermont, Vermont Geological Survey, Bull. 9.
Stone, S. W. and Dennis, J. G., 1964, The Geology of the Milton Quadrangle, Vermont, Vermont Geological Survey Bull. 26.
Additional reports on the geology of Vermont state parks distributed by the Vermont State Library, Montpelier, Vermont 05602.
The Geology of Groton State Forest, by Robert A. Christman, 1956 The Geology of Mt. Mansfield State Forest, by Robert A. Christman, 1956 The Geology of the Calvin Coolidge State Forest Park, by Harry W. Dodge, Jr., 1959 Geology of Button Bay State Park, by Harry W. Dodge, Jr., 1962 The Geology of Darling State Park, by Harry W. Dodge, Jr., 1967
FOOTNOTES
[1]A “strike” measurement is expressed as so many degrees east or west of north or south. For a diagram illustrating the dip and strike of a rock layer see [Figure 3].