Outlines of the Geology of Western Massachusetts
OUTLINES OF THE GEOLOGY OF WESTERN MASSACHUSETTS. TOPOGRAPHY. channels deeper. It is obvious that these exist details of fact which constitute the record are formations stand in their proper relative positions, ing conditions under which the plain is being described in the essay relating to each quadrangle. the oldest at the bottom. In order to follow this general description, destroyed are not those under which it was The greater portion of the rocks of the Green which is applicable to territory extending beyond formed. Mountains in Massachusetts were once horizontal ALGONKIAN PERIOD. the limits of the Holyoke quadrangle, Quadrangles To gain an idea of the manner of development beds of gravels, sands, clays, and marls, Origin of the In the usage adopted in this atlas the term the reader is referred to the following referred to- of the once level surface of the plateau, we may which became consolidated into con- rocks- "Archean" is applied to those most ancient crys topographic sheets of western Massachusetts: conceive the present process of gradual glomerates, sandstones, shales, and limestones. talline rocks which form part of the Greylock, Hawley, Greenfield, Becket, Chester wearing down carried to completion. They began to accumulate at a time remote in original crust of the earth and which ancient rocks 0 of this region, field, Northampton, Sandisfield, Granville, and When the streams shall have carved plateau- the geological past, when the region was invaded antedate and underlie the oldest sedi- Springfield, all on a scale of 1 mile to 1 inch. away the elevations now existing, the plateau by the sea.
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