On the northern side of the plateau runs Logan 's Fault marking the boundary between the geologic province of the Appalachian and of the Saint Lawrence Lowlands .
Logan 's Fault is a prominent area of inactive thrust faulting first documented by William Logan .
On the northern side of the plateau runs Logan 's Fault , a prominent area of inactive thrust faulting first documented by William Logan , marking the boundary between the geologic province of the Appalachian and of the Saint Lawrence Lowlands .