 At Rochester it flows over the precipitous edges of the Niagara limestone, forming the Upper Genesee Falls; and below it flows over the edge of the Medina sandstone, forming the Lower Genesee Falls.The principal tributaries of this stream are Canaseraga, Honeoye, and Conesus creeks from the south, and Oatka and Black creeks from the west.Honeoye, Canadice, Hemlock, and Conesus lakes—four of the Finger Lakes—lie within the Genesee Basin.