Conewango Valley is at the heart of the Chautauqua-Allegheny Region, and, in some ways, epitomizes it. Technically the Conewango watershed encompasses the Chautauqua Lake and Cassadaga Creek watersheds as well, which together cover nearly 900 square miles, most of it forest, wetlands, lakes and streams. Chautauqua Lake and Cassadaga Creek watersheds are treated separately here.
From its source near the edge of the Portage Escarpment to the Randolph-Steamburg area, Conewango Creek traverses the valley through which the Allegheny River once flowed but in the opposite direction, on its way to the valley now holding Lake Erie. Today the ancient valley lies buried under some 500 feet of rubble deposited by glaciers, which, in turn, lies beneath another 100 feet or so of lake-bottom silt. Snaking its way across the top of all this is present-day Conewango Creek, a stream that seems way too small for the great valley it occupies: “underfit,” say geologists.
Between Jamestown and Warren, however, a remarkable change occurs in the valley’s character. Valley walls tighten, funnel-like. Room for wetlands and croplands along the creek banks disappears. The depth of loose material covering bedrock shrinks from hundreds of feet to a few tens of feet. Students of local geology recognize this place, in the neighborhood of North Warren, as the Wisconsin glacier’s terminus, or end-point. The massive wall of ice reached just this far, and no farther.
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Natural History Atlas sites in the Conewango Creek Watershed include:
Erlandson Overlook County Park
Hatch Run Conservation Demonstration Area
Jamestown School Forest
Jamestown Audubon Nature Center
Rushing Stream Preserve