[Illustration: A Geological MAP _of a part of Massachusetts on_ Connecticut River 1817.] [Illustration: _Transverse Section of Rock Strata from Hoosack Mountain to Eleven Miles East of Connecticut River._] Williams' College is situated in a valley, having on the west the hills of the _Taconick_[48] range; on the east, _Saddle Mountain_, which separates it for the most part from Adams; and on the north, and northeast, two hills which belong to the southwestern part of the range of the _Green Mountains_. _Hoosack River_, rising several miles at the southeast, and passing through the northeastern part of Williamstown, winds its course northwest, to the Hudson. It is an inconsiderable stream, about six rods in width, and its current is rapid. From the south, runs _Green River_, a smaller stream, and enters the Hoosack one mile northeast of the college. The _green_ colour of this stream, appears to be caused by a _magnesian_ clay, which is washed from its banks at the south part of the town. At the west is _Westbrook_, rising in Williamstown, and entering the Hoosack one mile and a half northwest of the college. The _soil_ in this whole tract is generally _clayey_, rather light for such a soil, and very rich. A gravelly soil appears in a few places, especially at the northern part. The _interval_ on the Hoosack extends only a small distance from its banks, rarely exceeding, and often much less, than half a mile, and presents the common appearances of _alluvial_ land. Rising from ten to twenty feet above this interval, the soil is in various places filled with rolled stones of quartz and limestone, as if the Hoosack had once been much above the banks which confine it at present. It is not improbable that its waters were formerly intercepted by the hills in Pownal, five miles at the northwest, forming a small lake in this valley.