Many river valleys are strongly influenced by faults.  The Keweenaw Fault goes right through Houghton, crossing through the university ice arena, the Walker Center on campus, and then along the Keweenaw west of Torch Lake and up the Traprock Valley.  It separates flat-lying Jacobsville Sandstone from tilted lava flows.  The river is found along the fault, shifted to the SE because of the more easily eroded sandstone. The Pilgrim River valley is a watershed that has stayed in good ecological condition in spite of the development of Houghton and now citizens are making a big effort to build a community wide consensus plan for its preservation.  As such the Pilgrim River stands in contrast to the Huron Creek, on the other side of Houghton, where the river has been largely battered by development.