Before the glacier dam, Slippery Rock and Muddy creeks flowed north while extinct McConnells Run flowed south. The glacier dammed Lake Prouty on the edge of the drainage divide. Eventually Lake Pouty spilled over and rushed to the south, carving Slippery Rock Creek Gorge. Lakes Watts and Edmund drained into the gorge, digging it deeper and making Slippery Rock and Muddy creeks flow south. Areas of the deep Slippery Rock Gorge may be seen at nearby McConnells Mill State Park.
Before the glacier dam, Slippery Rock and Muddy creeks flowed north while extinct McConnells Run flowed south. The glacier dammed Lake Prouty on the edge of the drainage divide. Eventually Lake Pouty spilled over and rushed to the south, carving Slippery Rock Creek Gorge. Lakes Watts and Edmund drained into the gorge, digging it deeper and making Slippery Rock and Muddy creeks flow south. Areas of the deep Slippery Rock Gorge may be seen at nearby McConnells Mill State Park.